api-ms-win-crt-conio-l1-1-0.dll Missing on Windows: Fixes

If api-ms-win-crt-conio-l1-1-0.dll is missing, not found, or could not be loaded, repair or install the Microsoft Visual C++ Redistributable that matches the program, then update and repair Windows if the error continues. On 64-bit Windows, install both the x64 package for 64-bit programs and the x86 package for 32-bit programs when you are unsure which application architecture is failing.

What this file actually does

api-ms-win-crt-conio-l1-1-0.dll belongs to the Microsoft Universal C Runtime, usually encountered through the Visual C++ Redistributable runtime. The conio part refers to console input and output functions such as keyboard and character-based console routines documented by Microsoft in its console and port I/O reference.

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Despite ending in .dll, this is not an ordinary application library containing the complete implementation of those functions. It is an API-set contract, also described as a forwarder. Windows uses API-set names to route an application’s request to the appropriate runtime implementation. The underlying functionality is normally associated with ucrtbase.dll. Microsoft explains this API-set architecture in its documentation for Windows API sets.

That distinction matters because replacing only this one file often does not repair the real problem. The failure may involve:

• A missing or damaged Visual C++ Redistributable.
• A missing Universal C Runtime component.
• The wrong x86 or x64 runtime.
• A missing dependency of the named file.
• An incomplete application installation.
• An antivirus quarantine event.
• Corruption in the Windows component store.

The file can be centrally deployed as part of Windows or the Visual C++ runtime. A program can also carry its own app-local copy beside its executable. Microsoft documents both central UCRT deployment and app-local deployment in its Universal C Runtime deployment guide.

On ordinary 64-bit Windows installations, central runtime files are commonly located in:

• C:\Windows\System32 for the native 64-bit system architecture.
• C:\Windows\SysWOW64 for 32-bit runtime files.

Those folder names are counterintuitive. System32 is normally the 64-bit system directory on x64 Windows, while SysWOW64 contains 32-bit system files. Microsoft describes this layout in its Visual C++ deployment documentation.

There is no single universal file size or version that should exist on every Windows computer. Values vary by Windows build, servicing level, architecture, and whether the application uses an app-local runtime. A file being present on disk does not prove that it is the correct architecture, has not been corrupted, or is the copy Windows is trying to load.

Causes by symptom

What you see	Most likely cause	Best first action
One game or application fails, but other programs work	Incomplete application installation or app-local runtime problem	Repair the application or verify its files
Several Visual C++ applications fail	Missing, damaged, or mismatched runtime	Repair or install the matching x86 and x64 packages
Only a 32-bit program fails on 64-bit Windows	x86 Redistributable is missing	Install or repair vc_redist.x86.exe
Only a 64-bit program fails	x64 Redistributable or Windows component problem	Install or repair vc_redist.x64.exe
The file exists, but Windows still reports “not found”	Missing dependency, wrong architecture, or loader resolution problem	Repair the runtime and inspect the application installation
The message says “not designed to run on Windows”	Corruption, wrong file, invalid replacement, or incompatible architecture	Remove unofficial copies and repair Windows or the application
The error appeared after antivirus activity	The runtime or application file may have been quarantined	Check Windows Security Protection History
Windows 7 or 8.1 reports the file is missing	Universal CRT update or servicing prerequisite is missing	Install the applicable Universal CRT update and compatible Redistributable
The error started immediately after an update or installation	Damaged update or changed runtime	Try System Restore if a suitable restore point exists
Driver, DirectX, or .NET software was recently changed	Possible coincidence unless that installer specifically bundles the runtime	Repair Visual C++ first rather than reinstalling unrelated components

Fix 1: Repair or install the correct Visual C++ Redistributable

This is the most direct fix for a vcredist runtime error.

Microsoft provides the current supported packages on its Latest Supported Visual C++ Redistributable Downloads page. The relevant installers are:

• vc_redist.x86.exe for 32-bit applications.
• vc_redist.x64.exe for 64-bit applications.
• vc_redist.arm64.exe for applications requiring the ARM64 runtime.

The architecture of the program matters, not just the architecture of Windows. A 32-bit game running on 64-bit Windows needs the x86 package. Installing only x64 does not provide the 32-bit runtime that program needs.

If you are repairing a normal 64-bit Windows PC and do not know which application architecture is failing, install or repair both x86 and x64. This is common because one computer may run 32-bit games, 64-bit productivity software, older installers, and browser-related tools at the same time.

Repair an existing package

1. Press Windows and search for Installed apps.
2. Open Installed apps in Windows 11.

On Windows 10, open Settings > Apps > Apps & features.

1. Search for Microsoft Visual C++.
2. Look for the applicable Redistributable entries.
3. Select the three-dot menu beside an entry.
4. Choose Modify.
5. In the installer window, select Repair.
6. Repeat for the x86 and x64 entries if both are installed.
7. Restart Windows.
8. Launch the affected program again.

You can also use the older Control Panel interface:

1. Press Windows + R.
2. Enter appwiz.cpl.
3. Press Enter.
4. Select the relevant Microsoft Visual C++ Redistributable entry.
5. Choose Change.
6. Select Repair.
7. Restart the computer.

Microsoft documents this repair process and related installation failures in its Visual C++ Redistributable troubleshooting guide.

A successful repair usually allows the program to start without the DLL message. If the installer says that repair is unavailable, install the appropriate package from Microsoft’s download page, restart, and test again.

Install the package from Microsoft

Use Microsoft’s official download page rather than searching for the DLL filename. Choose the package based on the program:

• Install x86 for a 32-bit program.
• Install x64 for a 64-bit program.
• Install both x86 and x64 when multiple programs are affected or the architecture is unclear.
• Use ARM64 only when the affected software and Windows installation require it.

The current v14 package covers the modern Visual C++ runtime family, but older applications may also require older side-by-side runtimes, such as Visual C++ 2013 or earlier. Do not remove older Visual C++ entries simply because a newer package is installed. Microsoft states that older Visual C++ runtimes remain side by side, while the v14 family is compatible across supported toolsets. The application’s Windows-version and architecture requirements still apply.

If installation fails with an “already installed” message, use Modify > Repair on the existing entry. If it reports that the update is not applicable, check the Windows version, application architecture, and package requirements before trying a different installer.

Fix 2: Repair the application or verify the game files

If only one program reports api-ms-win-crt-conio-l1-1-0.dll, the problem may be inside that program’s installation rather than Windows.

Many applications install runtime files beside their executable. If that local copy is missing or damaged, repairing the system-wide Visual C++ package may not be enough.

Repair a desktop program

1. Press Windows + R.
2. Enter appwiz.cpl.
3. Press Enter.
4. Find the affected application.
5. Right-click it.
6. Choose Repair, Change, or Modify, depending on what the installer provides.
7. Complete the repair.
8. Restart Windows if requested.
9. Start the application again.

On Windows 11, some applications can also be repaired from:

1. Open Settings.
2. Select Apps > Installed apps.
3. Find the program.
4. Open its three-dot menu.
5. Choose Advanced options if available.
6. Select Repair.

Windows 10 provides a similar path through Settings > Apps > Apps & features.

If the program has no repair option, uninstall it and reinstall it from the original vendor installer. Do not delete individual DLLs from the installation directory before reinstalling. The installer may need to remove and recreate several related runtime files.

Verify a Steam game

For a Steam game:

1. Open Steam.
2. Select Library.
3. Right-click the game.
4. Choose Properties.
5. Select Installed Files.
6. Choose Verify integrity of game files.
7. Wait for the verification to finish.
8. Restart Steam and launch the game.

Verify an Epic Games game

For an Epic Games installation:

1. Open the Epic Games Launcher.
2. Open Library.
3. Select the three dots beside the game.
4. Choose Manage.
5. Select Verify.
6. Wait for the process to finish.
7. Launch the game again.

Game verification is especially appropriate when the problem began after an interrupted update, a crash during installation, or an antivirus quarantine event. It restores files from the game’s trusted distribution channel instead of encouraging manual DLL replacement.

Fix 3: Install Windows updates

Windows 10 and Windows 11 include the Universal C Runtime as part of the operating system. If its components are damaged, outdated, or incompletely serviced, Windows Update is the safest first repair mechanism.

Update Windows 11

1. Open Start > Settings.
2. Select Windows Update.
3. Choose Check for updates.
4. Install all available updates.
5. Restart when prompted.
6. Return to Windows Update.
7. Check again until Windows reports that no further updates are available.
8. Test the affected application.

Update Windows 10

1. Open Start > Settings.
2. Select Update & Security.
3. Choose Windows Update.
4. Select Check for updates.
5. Install all available updates.
6. Restart the computer.
7. Check for updates again.
8. Test the program.

Microsoft’s general instructions are available in its Windows Update installation guide.

If Windows Update reports that everything is current but the error remains, continue with DISM and SFC. Do not assume that the absence of pending updates proves the runtime is healthy.

Fix 4: Repair Windows with DISM and SFC

Use these commands when:

• Several applications fail with DLL or Bad Image errors.
• Windows Update cannot repair the issue.
• The error began after a failed update.
• The Visual C++ Redistributable is installed but Windows still cannot load the runtime.
• The file exists in the expected folder but Windows reports corruption or a loading failure.

Microsoft recommends running DISM before SFC because DISM repairs the component source that SFC uses.

Run DISM

1. Open Start.
2. Search for Command Prompt.
3. Right-click Command Prompt.
4. Choose Run as administrator.
5. Approve the User Account Control prompt.
6. Enter:

DISM.exe /Online /Cleanup-Image /RestoreHealth

1. Press Enter.
2. Wait for the operation to reach completion. It can remain at one percentage for a while.
3. Restart Windows when it finishes.

Do not close the window merely because progress appears to stop. If DISM reports that the restore operation completed successfully, continue with SFC.

Run System File Checker

After DISM completes:

1. Open an elevated Command Prompt again.
2. Enter:

sfc /scannow

1. Press Enter.
2. Wait until verification reaches 100 percent.
3. Restart Windows.
4. Launch the affected program.

A result stating that no integrity violations were found means SFC did not identify damaged protected system files. A result stating that corrupt files were repaired means you should restart and test again. If SFC could not repair some files, run DISM again after confirming that Windows Update is working, then rerun SFC.

If Windows cannot obtain repair files through Windows Update, Microsoft documents the use of a matching repair source with:

DISM.exe /Online /Cleanup-Image /RestoreHealth /Source:C:\RepairSource\Windows /LimitAccess

Do not use an arbitrary folder as the repair source. It must contain compatible Windows installation files.

Repeating SFC without recording its result rarely adds useful information. If these commands do not resolve the issue, note the exact result and move to application repair, antivirus review, or System Restore.

If you would rather avoid hunting through Windows component errors and repeating SFC or DISM without knowing what changed, Outbyte PC Repair can scan for problems and show what it finds; the repair is performed by the full version, while manual Windows repair remains available and appropriate.

Fix 5: Check antivirus quarantine

Antivirus software can quarantine a legitimate runtime file, particularly after an interrupted installation or when a program’s files were modified. This is a possibility, not proof that antivirus caused the error.

Check Windows Security Protection History

1. Open Start.
2. Search for Windows Security.
3. Open it.
4. Select Virus & threat protection.
5. Choose Protection history.
6. Review recent events.
7. Open any event related to the affected program or runtime.
8. Check the file path and detection details.

Microsoft explains the risks of restoring quarantined items in its Windows Security Protection History guidance.

Restore a file only when all of the following are true:

• The original application came from a trusted vendor or official store.
• The event clearly identifies the affected program or runtime.
• The file is part of the official installer.
• A security scan does not indicate broader malware activity.

If the installer came from an untrusted source, do not restore the file merely to make the application start. Remove the application, scan the computer, and reinstall it from the vendor’s trusted distribution channel.

After restoring a legitimate game file, verify the game installation through Steam or Epic. Do not permanently disable antivirus protection or create a broad exclusion for the Windows directory.

Fix 6: Use the correct package for the program architecture

Architecture errors are common because the Windows architecture and application architecture are separate.

A 64-bit Windows computer can run both:

• 64-bit applications using the x64 runtime.
• 32-bit applications using the x86 runtime.

The fact that Windows itself is 64-bit does not mean every program needs x64. Older games, utilities, installers, and business applications are frequently 32-bit.

Use this rule:

Affected program	Required package
32-bit application	x86
64-bit application	x64
Multiple applications of both types	x86 and x64
ARM64 application on compatible Windows	ARM64
Unknown architecture on 64-bit Windows	Install or repair x86 and x64

If the program’s installer has separate x86 and x64 versions, use the matching one. If the vendor describes the program as Win32 or 32-bit, use x86. If you cannot establish the architecture and the computer is 64-bit, installing both official packages is generally the practical repair path.

Do not copy an x64 DLL into a 32-bit application folder or an x86 DLL into a 64-bit application folder. A file can have the right name and still be unusable.

Fix 7: Handle Windows 7 or Windows 8.1 separately

Although this error is often reported on Windows 10 and Windows 11, some older computers still run Windows 7 or Windows 8.1. Their UCRT deployment path is different.

Microsoft’s original Universal C Runtime update for older Windows is KB2999226, Update for Universal C Runtime in Windows.

On Windows 7, KB2999226 requires Windows 7 SP1. Microsoft provides separate packages:

• Windows 7 x86 KB2999226 package
• Windows 7 x64 KB2999226 package

The general process is:

1. Press Windows + R.
2. Enter winver.
3. Press Enter.
4. Confirm the Windows edition and service pack.
5. Open Control Panel > System and Security > Windows Update.
6. Install available updates.
7. Restart.
8. Check for updates again.
9. Install the applicable KB2999226 package if Windows Update does not provide it.
10. Install the compatible Visual C++ Redistributable for the affected application.
11. Restart and test the program.

Windows 8.1 users should confirm that the required servicing prerequisites, including KB2919355 where applicable, are installed. Older Windows 7 systems may also require servicing-stack and SHA-2 support updates, including KB4490628 and KB4474419, before later packages can install. Microsoft describes those requirements in its SHA-2 code-signing support guidance.

The newest Visual C++ Redistributable permalink is not automatically suitable for Windows 7. Microsoft’s current documentation distinguishes newer Windows support from Visual Studio-era packages that supported Windows 7 SP1. On Windows 7, follow the application vendor’s supported runtime instructions and install KB2999226 rather than repeatedly trying the newest package.

If an installer says “not applicable,” check:

• Windows edition.
• Service pack.
• x86 or x64 architecture.
• Pending restart.
• Required servicing-stack updates.
• Windows Update error code.

Fix 8: Do not use regsvr32 for this file

regsvr32 is not a general DLL repair command. It is used for DLL or OCX files that provide a registration entry point such as DllRegisterServer.

Do not run:

regsvr32 api-ms-win-crt-conio-l1-1-0.dll

This file is an API-set forwarder associated with the Universal C Runtime. Registering it will not install the runtime, repair Windows component corruption, resolve an x86/x64 mismatch, or restore a missing dependency.

Use regsvr32 only when the software vendor specifically tells you to register a self-registering COM DLL or OCX and provides the correct file and command. Microsoft explains the correct scope of the utility in its Regsvr32 troubleshooting guidance.

Fix 9: Do not download the individual DLL

Downloading api-ms-win-crt-conio-l1-1-0.dll from a random DLL website is risky and frequently ineffective. The file may be malicious, the wrong architecture, an incompatible version, or an incomplete substitute for several missing runtime components.

It may also place an app-local copy in a location that causes Windows to load the wrong file. A copied DLL does not repair:

• The Visual C++ Redistributable installation.
• The Universal C Runtime component.
• A missing dependency.
• Windows component-store corruption.
• A failed application installation.
• An antivirus quarantine event.

Use these safe sources instead:

• Windows Update.
• DISM and SFC.
• Microsoft’s official Visual C++ Redistributable download page.
• The original application or game installer.
• The application’s repair or file-verification function.
• Microsoft’s official KB2999226 package for applicable older Windows installations.

Microsoft’s UCRT deployment documentation also distinguishes legitimate developer-controlled app-local deployment from end-user copying. App-local deployment is a packaging decision made by the software developer, not a recommendation to obtain a DLL separately.

Fix 10: Check Windows Features only when the program asks for them

Windows Features are not the normal source of api-ms-win-crt-conio-l1-1-0.dll. Enabling random features, especially unrelated .NET or legacy components, will not install the correct Universal C Runtime.

To inspect Windows Features:

1. Press Windows + R.
2. Enter:

optionalfeatures

1. Press Enter.
2. Review the available features.
3. Cancel unless the affected application specifically requires a feature and its vendor documents that requirement.

If the program separately reports a missing optional Windows feature, follow that program’s requirements. Do not treat Windows Features as a substitute for the Visual C++ Redistributable.

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Fix 11: Update drivers only when there is evidence

Graphics, chipset, audio, printer, and storage drivers do not normally provide this UCRT file. Reinstalling a graphics driver is not a justified general solution for this filename.

Driver work is relevant when:

• The error occurs inside a specific hardware vendor’s installer.
• The vendor confirms that its installer bundles a runtime prerequisite.
• Device Manager shows a separate device problem.
• The program’s own crash report identifies a driver failure in addition to the DLL error.

To check Device Manager:

1. Press Windows + X.
2. Select Device Manager.
3. Expand the relevant category, such as Display adapters or Sound, video and game controllers.
4. Right-click the affected device.
5. Choose Properties.
6. Review the General tab for a device status error.
7. Open the Driver tab to review the provider, date, and version.
8. Use Update Driver > Search automatically for drivers only when a driver update is actually indicated.
9. Restart Windows and retest.

For a clean reinstall, use the hardware manufacturer’s official driver package and follow its removal instructions. Do not remove a working driver simply because this DLL error appeared.

If you are dealing with several stale devices and do not want to hunt through driver versions manually, Outbyte Driver Updater can scan and show which drivers need attention; the driver installation is performed by the full version, and driver work remains unnecessary when the evidence points only to Visual C++.

Fix 12: Try System Restore after a recent change

System Restore is appropriate when the error began immediately after:

• A Windows update.
• A runtime installation.
• A driver installation.
• A major application change.
• A system configuration change.

It is not useful if there is no restore point from before the problem.

To start System Restore:

1. Press Windows + R.
2. Enter:

rstrui.exe

1. Press Enter.
2. Select Next.
3. Choose a restore point dated before the DLL error began.
4. Select Scan for affected programs if available.
5. Review the changes.
6. Select Next.
7. Confirm the restore point.
8. Choose Finish.
9. Allow Windows to restart.

Microsoft states that System Restore rolls back system files, settings, and installed programs without affecting personal files. It does not replace a backup, and applications installed after the selected restore point may need to be installed again. The procedure is described in Microsoft’s System Restore guidance.

Advanced diagnosis when the file exists

A file can appear in System32, SysWOW64, or the application folder and still fail to load.

Common explanations include:

• The application needs x86 but only x64 runtime files are available.
• The application needs x64 but is finding an incompatible local copy.
• Another dependency of the API-set forwarder is missing.
• The program is loading an app-local copy instead of the centrally deployed runtime.
• The file is corrupted.
• Windows loader search rules are selecting a different location.

Microsoft documents how Windows searches for DLL dependencies in its dynamic-link library search-order reference.

Use this sequence:

1. Note the full path shown in the error, if one is provided.
2. Check whether the failure affects one program or multiple programs.
3. Repair both x86 and x64 Visual C++ packages on a 64-bit computer when architecture is unclear.
4. Repair or verify the affected application.
5. Look for suspicious copies in temporary folders or user-profile directories.
6. Run DISM and SFC if multiple Windows programs fail.
7. Check antivirus Protection History.
8. Restart after each completed repair stage.
9. Test the original application again.

Do not replace a suspicious file with one copied from another computer. Two computers can have different Windows builds, architecture, servicing levels, and runtime dependencies.

If the message says “the specified module could not be found,” that wording does not always mean the named DLL itself is absent. A dependency required by the named file may be missing, or the Windows loader may be unable to resolve the requested architecture.

When the problem is probably not this DLL

Do not start with DirectX, .NET, or a graphics-driver reinstall unless the program reports a separate error involving one of those components.

This file is not inherently:

• A graphics driver.
• A printer driver.
• A DirectX component.
• A .NET Framework component.
• A game-specific library.
• A hardware firmware file.

If one game fails, verify that game first. If every Visual C++ application fails, repair the runtime and Windows. If every program reports Bad Image errors, prioritize malware checks, disk health, DISM, SFC, and possible Windows repair over copying files into multiple folders.

A suspicious copy in a temporary directory or a user profile should be treated carefully. Check which installer created it, scan the system, and reinstall the affected program from a trusted source.

Frequently asked questions

Is api-ms-win-crt-conio-l1-1-0.dll a Windows file?

It can be. On Windows 10 and Windows 11, the Universal C Runtime is part of the operating system. Applications can also carry an app-local copy of the UCRT beside their executable, so the exact location depends on how the program was deployed.

Is it part of Visual C++?

Yes. It is part of the Universal C Runtime used by Visual C++ applications. The matching Visual C++ Redistributable is the correct installation path for most application-level errors.

Does 64-bit Windows need the x86 package?

Yes, when the affected program is 32-bit. A 64-bit operating system can run 32-bit applications, and those applications need the x86 Redistributable. Many computers need both x86 and x64 packages.

Why does reinstalling the application sometimes not help?

The installer may assume that the runtime is already present, fail to install its prerequisite, or contain an incomplete app-local runtime. Windows component corruption or antivirus quarantine can also survive an application reinstall.

Why does the error remain when the file exists?

The file may be the wrong architecture, corrupted, or not the copy Windows is loading. Another dependency may be missing, or an app-local copy may be interfering with the centrally deployed runtime.

Should I register the file with regsvr32?

No. API-set forwarders and Visual C++ runtime files are not repaired by registering them. regsvr32 applies to self-registering DLLs and OCXs that provide the required registration entry point.

Should I copy the file into System32?

No. Manual copying can introduce malware, the wrong architecture, or an incompatible version. Repair the official runtime, Windows, or the affected application instead.

What should I do after antivirus quarantines it?

Open Windows Security > Virus & threat protection > Protection history and inspect the event. Restore the file only when the application came from a trusted source and the file is confirmed to be part of that official installation. Otherwise, scan the computer and reinstall the program from its trusted source.

Does Windows Features fix this problem?

Usually not. Windows Features do not replace the Visual C++ Redistributable or repair the Universal C Runtime. Use them only when the application separately requires a documented optional Windows feature.

Is KB2999226 needed on Windows 10 or Windows 11?

The update is primarily relevant to older Windows versions such as Windows 7 SP1 and Windows 8.1. Windows 10 and Windows 11 include the UCRT through the operating system, so use Windows Update, the Visual C++ repair process, DISM, and SFC instead.

What information should I provide if the error persists?

Record:

• Windows edition and build from winver.
• Whether the computer is x64 or ARM64.
• The exact application or game name.
• The complete error message.
• Whether one program or several programs fail.
• Whether the program is 32-bit or 64-bit, if known.
• Which Visual C++ Redistributable entries are installed.
• Whether x86, x64, or both packages were repaired.
• The final DISM and SFC results.
• Any Windows Update error code.
• Any antivirus Protection History event and file path.
• Whether the problem began after an update, driver installation, or interrupted application install.

That information separates an application-local failure from a Windows-wide runtime or component-store problem and prevents unnecessary DLL copying.

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