atl90.dll Is Missing: Fix Runtime Errors on Windows 10 and 11

atl90.dll is a Microsoft Visual C++ 2008 runtime file that an older program or game needs to start. If Windows says atl90.dll was not found, could not be loaded, or is missing, install or repair the matching Visual C++ 2008 runtime before trying more advanced repairs.

Quick identification

Item	Details
File	atl90.dll
Runtime family	Microsoft Visual C++ 2008, also called Visual C++ 9.0
Component	Active Template Library shared runtime code
Category	Visual C++ Redistributable
Normal Windows status	Not a standard inbox Windows DLL like kernel32.dll
Typical deployment	Visual C++ redistributable, application installer, or application-local files
Common locations	Windows side-by-side assembly storage, often under WinSxS, or the affected program’s own folder
File description	Not reliably listed in the file metadata supplied by the application
Main fix	Install or repair the official Visual C++ 2008 SP1 redistributable

Known file listings can show different versions depending on the package, security update, architecture, and application that installed the file.

As an Amazon Associate I earn from qualifying purchases.

Architecture	Known version	Approximate listed size
32-bit	9.0.30729.6161	0.15 MB
32-bit	9.0.30729.4148	0.15 MB
32-bit	9.0.30729.1	0.15 MB
64-bit	9.0.21022.8	0.11 MB

Do not treat a different file version by itself as proof that the file is wrong. Microsoft’s package version and the version resource inside an individual runtime DLL can differ.

The safest fix: install Visual C++ 2008 SP1

The most likely cause is a missing or damaged Visual C++ 2008 runtime. The package that normally fixes this error is Microsoft’s Visual C++ 2008 Service Pack 1 Redistributable Package MFC Security Update.

This is the important architecture rule:

• A 32-bit program needs vcredist_x86.exe.
• A 64-bit program needs vcredist_x64.exe.
• A 64-bit version of Windows can run both types of programs, so many computers need both packages.

The architecture of Windows and the architecture of the application are not the same thing. A 64-bit Windows installation frequently needs the x86 runtime because many older desktop applications and games are 32-bit.

Install the correct package

1. Close the program showing the atl90.dll error.
2. Open Microsoft’s Visual C++ 2008 SP1 Redistributable download page.
3. Select the download option.
4. Choose vcredist_x86.exe if the affected application is 32-bit.
5. Choose vcredist_x64.exe if the affected application is 64-bit.
6. On 64-bit Windows, install both packages when the application architecture is unknown or several programs are affected.
7. Run the downloaded installer.
8. Accept the license terms.
9. Select Install. If Visual C++ 2008 is already installed, the installer may offer Repair instead.
10. Complete the repair or installation.
11. Restart Windows.
12. Start the affected application again.

If you are unsure which architecture the application uses, installing both x86 and x64 packages on 64-bit Windows is the practical route. Installing both does not make the x86 package a replacement for x64, or the other way around. Each package serves a different process architecture.

Check Windows architecture

To check the operating system architecture:

1. Right-click Start.
2. Select System.
3. Scroll to Device specifications.
4. Read System type.

This tells you whether Windows is 32-bit or 64-bit, but it does not always identify the architecture of a particular application. Application documentation, the installer package, and the process information in Task Manager can help identify the program.

On a 32-bit version of Windows, install the x86 package. A 32-bit version of Windows cannot run a 64-bit application.

What success looks like

The fix worked if:

• the program opens normally;
• the atl90.dll message no longer appears;
• the program reaches its sign-in screen, main menu, or normal interface;
• a launcher no longer reports a missing runtime component.

If the same error remains after installing the correct package, continue with application repair and side-by-side diagnosis. Do not immediately download a loose replacement DLL.

Do not substitute a newer Visual C++ package

Visual C++ runtime generations are separate. Visual C++ 2008 uses the VC90 runtime and files including atl90.dll. Other generations use different files, including atl80.dll, atl100.dll, and atl110.dll.

Installing Visual C++ 2010, 2013, 2015, 2019, or 2022 does not automatically replace the Visual C++ 2008 runtime. Microsoft lists the generations and architecture requirements on its Latest supported Visual C++ Redistributable downloads page.

Keep other Visual C++ redistributables installed unless you know exactly which application no longer needs them. Older programs commonly depend on a specific runtime generation.

Repair the affected program

If only one application fails, its own installation may be damaged. The program may have lost a private copy of atl90.dll, a Visual C++ manifest, or another VC90 dependency.

Repair from Windows Settings

For a modern desktop application:

1. Open Settings.
2. Select Apps.
3. Select Installed apps.
4. Find the affected application.
5. Select the three-dot menu beside it.
6. Select Advanced options, if available.
7. Select Repair.
8. Start the application again.

Use Reset only when repair does not help and you understand that the application may lose local settings or cached data.

Repair from Control Panel

For a traditional desktop program:

1. Press Win + R.
2. Type appwiz.cpl.
3. Press Enter.
4. Find the application in Programs and Features.
5. Right-click it.
6. Select Repair or Change, depending on the installer.
7. Follow the repair wizard.
8. Restart Windows if requested.
9. Test the application.

If there is no repair option, uninstall the program and reinstall it from the original vendor installer, the official launcher, or the original installation media. Reinstalling the program is the definitive fix when the program itself owns the damaged or missing runtime files.

Verify game files

Interrupted updates, disk cleanup, antivirus quarantine, and damaged game files can remove a runtime file that a game expects to find.

For a Steam game:

1. Open Steam.
2. Select Library.
3. Right-click the game.
4. Select Properties.
5. Select Installed Files.
6. Select Verify integrity of game files.
7. Wait for the process to finish.
8. Start the game again.

For an Epic Games Launcher title:

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

If verification restores the file but the error returns, repair the Visual C++ 2008 runtime as well. A launcher can restore application files, but it may not repair a shared runtime installed separately.

Understand where atl90.dll may be stored

atl90.dll may not be visible in C:\Windows\System32, and that does not automatically mean it is missing.

Visual C++ 2008 applications can use side-by-side assemblies. The runtime may be stored in the Windows component and assembly store under WinSxS, selected through a manifest. An application can also use a private runtime directory beside its executable.

This explains several confusing situations:

• File Explorer cannot find atl90.dll in System32, but the application works.
• A loose copy exists somewhere on the disk, but the application still fails.
• The error names atl90.dll, while the actual failure involves a manifest or another VC90 dependency.
• A 32-bit program fails even though a 64-bit runtime file exists.
• Replacing a file in a Windows directory does not repair the assembly registration or version selection.

Microsoft describes these deployment choices in Choosing a deployment method.

The loader does not simply search every folder for a file with the right name. It also considers architecture, manifests, assembly identity, dependency versions, and the location from which the application is loading the runtime.

When the error mentions Microsoft.VC90.ATL

Microsoft.VC90.ATL is the side-by-side assembly identity associated with the Visual C++ 2008 ATL runtime.

An installer or application may show an error similar to:

Error 1935. An error occurred during the installation of assembly
Microsoft.VC90.ATL ...

This usually indicates that Windows could not install or activate the required VC90 ATL assembly. It is not the same as a simple missing loose file.

The correct first steps are:

1. Restart Windows.
2. Run the official Visual C++ 2008 installer again as an administrator.
3. Select Repair if it is already installed.
4. Install the correct x86 or x64 package.
5. Repair or reinstall the application.
6. Check Event Viewer for a side-by-side event.
7. Run sxstrace if the failure remains.

Microsoft also publishes an older Visual C++ 2008 SP1 ATL Security Update. Use the main MFC Security Update as the normal starting point. The ATL-specific package is relevant when an older installer or vendor instruction explicitly requires it.

Diagnose “side-by-side configuration is incorrect”

A side-by-side error means the Windows loader could not resolve the application’s requested assembly configuration. The problem may be a missing assembly, incorrect version, wrong architecture, missing manifest, or another dependency.

Common messages include:

This application has failed to start because the application configuration is incorrect.
Reinstalling the application may fix this problem.

The application failed to initialize properly (0xc0000135).

A message that names atl90.dll can still be caused by another file, including:

• msvcr90.dll;
• msvcp90.dll;
• a missing or invalid VC90 manifest;
• an incompatible private copy;
• a damaged executable;
• the wrong x86 or x64 runtime.

Check Event Viewer

1. Press Win + R.
2. Type eventvwr.msc.
3. Press Enter.
4. Expand Windows Logs.
5. Select Application.
6. Look for an event with the source SideBySide.
7. Open the event.
8. Read the assembly name, version, processor architecture, and application path.

If the event identifies Microsoft.VC90.ATL, install or repair Visual C++ 2008. If it identifies another assembly, repair the same runtime generation and application rather than replacing `atl90.dll alone.

Trace the loader with sxstrace

For a detailed diagnosis, open an elevated Command Prompt:

1. Open Start.
2. Type Command Prompt.
3. Right-click Command Prompt.
4. Select Run as administrator.
5. Run:

sxstrace.exe trace -logfile:C:\sxstrace.etl

1. Reproduce the application error.
2. Return to the elevated Command Prompt.
3. Stop tracing:

sxstrace.exe stoptrace

1. Convert the trace to readable text:

sxstrace.exe parse -logfile:C:\sxstrace.etl -outfile:C:\sxstrace.txt

1. Open the report:

notepad C:\sxstrace.txt

Look for the missing assembly name, requested version, processor architecture, and the path Windows attempted to load.

Microsoft documents these commands on the sxstrace reference page.

Check antivirus Protection History

Antivirus software may quarantine a runtime file bundled with an old program. This is especially common after an application update, a repair attempt, or a security definition change.

To inspect Microsoft Defender’s records:

1. Open Start.
2. Type Windows Security.
3. Open the application.
4. Select Virus & threat protection.
5. Select Protection history.
6. Review recent detections.
7. Open any item related to the affected program or atl90.dll.

Restore a quarantined file only when you trust the original application and can verify that the file came from the official installer. Restoring an unsafe file can cause Defender to detect it again.

The safer sequence is usually:

1. Note the detection name and affected path.
2. Remove or leave the item quarantined.
3. Reinstall the official Visual C++ package.
4. Repair or reinstall the application.
5. Update the application from its official source.
6. Run another security scan.

Do not create a broad antivirus exclusion merely to make an old program start. If the file is repeatedly quarantined, contact the application vendor or replace the application with a supported version.

Repair Windows components with DISM and SFC

SFC and DISM are not the primary fix for an application-local Visual C++ runtime. They become relevant when:

• several unrelated applications fail;
• Windows reports component-store corruption;
• the Visual C++ installer cannot service Windows components;
• multiple system components are damaged;
• the problem began after a failed update or storage problem.

Run DISM before SFC.

1. Open Start.
2. Type Terminal.
3. Right-click Windows Terminal.
4. Select Run as administrator.
5. Run:

DISM /Online /Cleanup-Image /RestoreHealth

1. Wait for DISM to finish.
2. Then run:

sfc /scannow

1. Wait until the verification reaches 100 percent.
2. Restart Windows.
3. Test the affected program again.
4. If it still fails, repair or reinstall the Visual C++ package and application.

DISM repairs the Windows component store. SFC checks protected Windows system files. Neither command reliably reconstructs a private VC90 deployment inside an application folder.

Running DISM and SFC manually can mean repeating long checks without knowing what changed. Outbyte PC Repair offers a free scan that shows exactly what it identifies; repair is performed by the full version, and it is optional because a program-specific VC++ deployment still requires repairing or reinstalling that program.

Microsoft’s instructions for these commands are available in Use the System File Checker tool to repair missing or corrupted system files.

Install pending Windows updates

A recent servicing failure or incomplete update can interfere with runtime installation.

1. Open Settings.
2. Select Windows Update.
3. Select Check for updates.
4. Install available updates.
5. Restart Windows.
6. Run the Visual C++ 2008 installer again.
7. Test the affected application.

Windows Update does not replace the need for the Visual C++ 2008 runtime. It can repair the operating system conditions that prevent the runtime installer from completing.

Use System Restore after a recent system change

System Restore is relevant when the problem began immediately after:

• a driver installation;
• a cleanup utility;
• an application removal;
• a Windows update;
• a security product change;
• a system configuration change.

To open System Restore:

1. Press Win + R.
2. Type:

rstrui.exe

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

System Restore rolls back system files, settings, and installed programs, but it normally does not remove personal files. Microsoft explains the process in its System Restore documentation.

After the restore completes, reinstall the application or Visual C++ runtime if necessary.

Driver and device-package checks

A driver reinstall is not a normal fix for atl90.dll. It becomes relevant when the error identifies a hardware utility, scanner package, control panel, industrial application, device-management tool, or other vendor program that bundled Visual C++ 2008.

Use the hardware vendor’s complete software package rather than downloading a standalone DLL.

Check drivers through Device Manager

1. Right-click Start.
2. Select Device Manager.
3. Expand the category related to the affected hardware.
4. Right-click the device.
5. Select Properties.
6. Open the Driver tab.
7. Review the driver provider and date.
8. Select Update Driver.
9. Select Search automatically for drivers.
10. Restart Windows if a driver is installed.
11. Reinstall the vendor’s control software if the atl90.dll error belongs to that software.

If the error began immediately after a driver update, open the same Driver tab and select Roll Back Driver when the option is available.

Manually checking dozens of driver versions is slow and makes it difficult to know which device caused the change. Outbyte Driver Updater offers a free scan that identifies the drivers it finds; installation is performed by the full version, while the hardware vendor’s complete package remains the definitive source for software that specifically requires atl90.dll.

Do not reinstall a display, chipset, printer, or storage driver solely because the filename looks like a driver dependency. Confirm that the affected program belongs to that hardware package first.

Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Support on Ko-Fi

Why Windows Features usually does not fix atl90.dll

The Windows Features dialog does not normally provide the Visual C++ 2008 ATL runtime.

To inspect it:

1. Press Win + R.
2. Type:

optionalfeatures

1. Press Enter.
2. Review the available Windows features.
3. Close the dialog without changing anything unless the affected application’s documentation specifically names a feature it requires.

Enabling .NET Framework, legacy components, or another unrelated Windows feature does not install atl90.dll. atl90.dll is not a DirectX file, not a .NET assembly, and not a normal Windows optional feature.

Use Windows Features only when the application gives a separate, specific feature error. For the atl90.dll failure itself, install Visual C++ 2008.

“Not designed to run on Windows” or “Bad Image”

A message that says the file is not designed to run on Windows, or that the application contains an invalid image, usually indicates one of these conditions:

• the file is corrupted;
• the file has the wrong architecture;
• the manifest is invalid;
• the application contains an incompatible private copy;
• antivirus software altered or quarantined a component;
• another dependency is damaged.

Use this order:

1. Install or repair the correct Visual C++ 2008 architecture.
2. Repair or reinstall the affected application.
3. Check Windows Security Protection History.
4. Run DISM and SFC if several applications are affected.
5. Use Event Viewer and sxstrace for side-by-side details.

Do not replace the file with an arbitrary copy from another computer. A file with the right name can still have the wrong architecture, version, signature, or dependency set.

What not to do

Do not download atl90.dll from a random DLL website

Loose DLL download sites can provide:

• malware;
• modified binaries;
• the wrong Visual C++ generation;
• the wrong x86 or x64 architecture;
• an incomplete set of dependent files;
• a file that does not match the application manifest.

A replacement file may make the first error disappear while leaving the actual runtime or assembly problem unresolved. Use Microsoft’s Visual C++ redistributable package or the application’s original installer instead.

Do not paste the file into System32 or SysWOW64

Copying a file into a Windows directory does not install the VC90 assembly, satisfy its manifest, repair side-by-side registration, or provide dependencies including msvcr90.dll and msvcp90.dll.

It can also create version conflicts for other applications.

Do not run regsvr32 atl90.dll

regsvr32 is used for a DLL that implements the COM DllRegisterServer entry point. It writes registration information to the registry for that particular COM component.

atl90.dll is a shared runtime library. Registering it does not install the Visual C++ 2008 assembly or repair a manifest. Microsoft documents the command’s purpose in the regsvr32 reference and explains the registration requirement in COM self-registration.

If a vendor specifically tells you to register its own COM DLL, use the vendor’s exact instructions and the correct architecture:

For a 64-bit COM DLL on 64-bit Windows:

%SystemRoot%\System32\regsvr32.exe "C:\Path\vendor-component.dll"

For a 32-bit COM DLL on 64-bit Windows:

%SystemRoot%\SysWOW64\regsvr32.exe "C:\Path\vendor-component.dll"

Those commands apply to the vendor’s COM component, not to atl90.dll.

Do not install only the newest Visual C++ runtime

The newest redistributable does not automatically satisfy every older runtime dependency. Install the VC++ 2008 package required by the application, then keep newer generations installed for programs that need them.

Do not remove every Visual C++ redistributable

Different programs may require different runtime generations and architectures. Removing unrelated entries from Apps or Programs and Features can create additional startup failures.

Special cases

Debug builds and old developer components

Some old developer tools and components require debug files including msvcr90d.dll. Debug runtime files are not a general end-user replacement for the normal redistributable.

If an old developer component fails with a debug dependency, install the exact vendor development package or rebuild the component as documented by its vendor. Do not copy debug DLLs from an unrelated development computer.

Windows CE

Windows CE applications can package runtime files differently from desktop Windows. A Windows CE device image or industrial deployment may require its own runtime files and deployment process.

Do not assume that the desktop x86 or x64 Visual C++ 2008 redistributable is suitable for a Windows CE application. Follow the device or software vendor’s deployment instructions.

Application-local deployment

Some programs carry private copies of runtime files beside their executable. This can be legitimate when the application vendor supplies the matching files and manifest.

Manual application-local deployment is appropriate only when:

• the vendor explicitly supplies the exact file and manifest;
• the file is verified as Microsoft-signed;
• the architecture matches the application;
• the requested runtime version matches;
• the vendor documents that deployment method.

For ordinary users, the central redistributable installer is safer and easier to service.

FAQ

What is atl90.dll?

atl90.dll is shared Active Template Library runtime code from Visual C++ 2008, also called Visual C++ 9.0. ATL supports components including COM objects, Automation servers, and ActiveX controls. Microsoft explains the role of ATL in Scope of ATL.

Is atl90.dll part of Windows 10 or Windows 11?

It is not normally an original inbox Windows component in the same category as core files including kernel32.dll. An application installer, Visual C++ redistributable, or private application deployment normally provides it.

Is atl90.dll part of DirectX or .NET?

No. It belongs to the Visual C++ 2008 ATL runtime. Installing DirectX or enabling .NET features does not replace the required VC90 runtime.

Why does 64-bit Windows need the x86 package?

Many programs running on 64-bit Windows are still 32-bit applications. A 32-bit process needs the x86 Visual C++ runtime. A 64-bit process needs x64. The operating system’s architecture does not determine the application’s runtime architecture.

Why are atl80.dll, atl90.dll, atl100.dll, and atl110.dll different?

They belong to different Visual C++ generations. The number identifies the runtime generation, so one file should not be substituted for another.

Why can the file be present in WinSxS but not System32?

Visual C++ 2008 can use side-by-side assembly deployment. Windows selects the correct runtime through assembly manifests and architecture information. The file does not need to appear as a loose file in System32 for a correctly configured application to use it.

Why does the error name atl90.dll when another file is missing?

The loader may report the first dependency that failed or the component named by the application manifest. The underlying issue can involve msvcr90.dll, msvcp90.dll, a manifest, a damaged executable, or the wrong architecture.

What does Microsoft.VC90.ATL mean?

It is the side-by-side assembly identity for the Visual C++ 2008 ATL runtime. An installer error naming it usually means that Windows could not install or activate the required VC90 assembly.

What does Error 1935 mean?

In this context, Error 1935 indicates that Windows could not install a required side-by-side assembly during the Visual C++ setup. Repair the correct VC++ 2008 package, check Event Viewer, and use DISM and SFC when Windows component-store corruption is also suspected.

Should I register atl90.dll with regsvr32?

No. regsvr32 is for COM DLLs that implement DllRegisterServer. It does not install or repair the Visual C++ 2008 ATL runtime assembly.

Should I run SFC for every atl90.dll error?

No. Start with the Visual C++ 2008 redistributable and application repair. Use DISM and SFC when multiple programs fail, Windows component servicing is damaged, or the runtime installer reports system-level errors.

When should I reinstall a driver?

Only when the affected application is clearly part of a hardware or device software package. A normal atl90.dll error does not indicate that a graphics, chipset, printer, or storage driver needs to be reinstalled.

What if every normal fix fails?

Collect:

• the complete error text;
• the error code, if shown;
• the affected executable’s full path;
• the application name and version;
• Windows edition, version, and architecture;
• whether one program or several programs fail;
• installed Visual C++ 2008 x86 and x64 entries;
• the sxstrace.txt report;
• the file path, version, size, and digital-signature status;
• antivirus Protection History results.

If only one application fails, contact that application’s vendor after repairing or reinstalling it. If many unrelated applications fail, investigate Windows servicing, malware, disk errors, or component-store corruption rather than treating the problem as an isolated atl90.dll file issue.

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.