The error messages
You may see one of these messages when launching a game or application:
- “The program can’t start because api-ms-win-core-processthreads-l1-1-1.dll is missing from your computer.”
- “The code execution cannot proceed because api-ms-win-core-processthreads-l1-1-1.dll was not found.”
- “api-ms-win-core-processthreads-l1-1-1.dll is either not designed to run on Windows or it contains an error.”
- “The procedure entry point could not be located in api-ms-win-core-processthreads-l1-1-1.dll.”
api-ms-win-core-processthreads-l1-1-1.dll is a Windows API-set contract name, not a normal third-party runtime DLL. The safest fix is usually to check whether your Windows build supports the application, then repair Windows and reinstall the affected program from its official source.
The 60-second answer
Do not download this filename from a random DLL website or copy it into System32. The name belongs to the Windows API-set system: the loader uses API-set contracts to redirect an application’s Windows API calls to the correct operating-system implementation.
Microsoft lists the process and thread APIs associated with this contract as requiring Windows version 10.0.16299, which corresponds to Windows 10 version 1709. That does not prove the cause of every individual error, but it makes an unsupported or outdated Windows build the first thing to investigate.
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Use this order:
- Check your Windows version and install pending updates.
- Determine whether one application or many applications fail.
- Repair or reinstall the affected application.
- Run DISM, followed by SFC, if Windows components may be damaged.
- Check Windows Security quarantine and the application’s launcher verification tool.
- Consider System Restore or a Windows repair reinstall if the failure affects the whole system.
Microsoft explains that API-set names ending in .dll are loader contracts and do not necessarily represent standalone files that should be copied or registered manually. See Microsoft’s documentation on Windows API sets and API-set loader operation.
What causes this error
An old or unsupported Windows build
This is the leading possibility when a newly installed application fails immediately, especially on Windows 7, Windows 8, Windows 8.1, or an older Windows 10 installation. The application may import APIs associated with a newer Windows API surface.
To check your build:
- Press
Windows + R. - Type
winver. - Press Enter.
- Note the Windows edition, version, and OS build.
On Windows 10 or Windows 11, open Settings > Windows Update and select Check for updates. Install available updates, restart, and try the program again.
If the application requires a Windows version newer than the one installed, system-file repair will not add that compatibility. Update Windows where supported, or install an older release of the application that explicitly supports your current operating system.
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A failed update, disk problem, cleanup utility, or other system change can damage the component store or protected Windows files. This is more likely when several unrelated programs fail, Windows Update behaves abnormally, or the error began after a system change.
A broken application installation
If only one game or program produces the message, its installation is the more likely target. The application may have an incomplete update, a damaged launcher, an incompatible bundled dependency, or a local file removed during installation.
Architecture or compatibility mismatch
A 32-bit application and a 64-bit application can load different dependencies. Installing an x86 file into a 64-bit program, or placing an x64 file into a 32-bit program, is not a safe repair.
Do not assume that a 64-bit version of Windows means every application is 64-bit. Check the publisher’s requirements, the installer name, or the application’s documentation. Use the official installer that matches both the program and your Windows architecture.
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Antivirus quarantine or disk damage
Windows Security may quarantine an application file after installation or an update. Disk corruption, malware, or a damaged user profile can also cause broader loading failures. Treat quarantine as a case-specific possibility, not proof that this API-set contract is normally removed by antivirus software.
Fix 1: Repair or reinstall the affected program
Start here when the error affects only one program.
Use Windows’ built-in repair option
For supported applications:
- Open Start > Settings.
- Select Apps > Installed apps.
- Find the affected application.
- Select the three-dot menu beside it.
- Choose Advanced options.
- Select Repair.
- Start the program again.
If Repair is unavailable or does not help, use Reset only if you understand that it may remove application data and settings. Otherwise, uninstall the program and reinstall it from the publisher’s official installer.
For a game launcher, look for options named Verify integrity, Verify files, Scan and repair, or Repair installation. These options compare the installed files with the launcher’s official copy. Restart the computer after verification completes.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsIf the application was installed from an unofficial package, remove it and obtain a clean installer from the developer or an authorized store. Do not replace one missing-looking filename with a download from a DLL repository.
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Check application permissions
If the program fails because it cannot access its own installation directory:
- Right-click the program’s shortcut.
- Select Properties.
- Open the Compatibility tab.
- Select Run this program as an administrator.
- Choose Apply, then OK.
- Launch the program once.
Administrator mode is a diagnostic step, not a substitute for fixing an incompatible application or permanently damaged installation. If it changes nothing, turn the setting back off and continue troubleshooting.
Fix 2: Install Windows updates
A current Windows installation is important when an application expects newer API-set support.
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- Select Windows Update.
- Choose Check for updates.
- Install all available quality, security, and feature updates that your edition supports.
- Restart Windows.
- Open Windows Update again and repeat the check until no further normal updates are offered.
If the computer runs an old Windows release that cannot receive the required update, install a program version compatible with that release or upgrade Windows. Do not try to make Windows 7 or another unsupported system compatible by copying one DLL from a newer computer.
Fix 3: Repair Windows with DISM and SFC
Run these commands when several programs fail, Windows updates are damaged, or the problem began after a system change.
- Open Start.
- Type
Command Prompt. - Right-click Command Prompt.
- Select Run as administrator.
- Approve the User Account Control prompt.
- Run this command:
DISM.exe /Online /Cleanup-image /Restorehealth
Wait for it to finish. DISM may use Windows Update as its repair source and can take time. When it completes, run:
sfc /scannow
Restart Windows after SFC finishes and test the affected program.
A message that SFC found and repaired corrupted files is a useful result. If SFC reports that it found no integrity violations but the program still fails, Windows may be healthy and the application may be incompatible or incorrectly installed. If SFC cannot repair some files, save the details with:
findstr /c:"[SR]" %windir%LogsCBSCBS.log > "%userprofile%Desktopsfcdetails.txt"
Do not manually replace this API-set component with a file copied from another Windows installation. DISM and SFC will not turn an unsupported Windows version into a supported one.
Repeating SFC and DISM without knowing what changed can make troubleshooting difficult. Outbyte PC Repair can scan and show what it identifies as a repair issue; the repair action requires the full version, and it is optional. Reinstalling the affected application remains the definitive fix when the failure belongs to that application.
Fix 4: Check Windows Security quarantine
Check this only if the failure began after an antivirus detection, application update, or cleanup event.
- Open Windows Security from the Start menu.
- Select Virus & threat protection.
- Choose Protection history.
- Review recent actions involving the affected program.
- Expand an item to see its path and detection details.
Restore or allow a file only when you trust its origin and can verify its publisher signature. If the file came from an unofficial installer, do not restore it. Uninstall the application and reinstall it from its official source instead.
Microsoft notes that restoring a quarantined file can cause Defender to detect it again. Read Microsoft’s guidance on Protection History before allowing anything back onto the system.
Fix 5: Check drivers and hardware changes
A driver is not the same thing as api-ms-win-core-processthreads-l1-1-1.dll, so driver replacement is not the primary repair. However, the failure may have started after a graphics, chipset, storage, or security-driver update.
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To inspect drivers:
- Right-click Start.
- Select Device Manager.
- Expand categories such as Display adapters, System devices, and Storage controllers.
- Look for a warning icon.
- Right-click a suspect device and select Properties.
- Review the General and Driver tabs.
- If the issue began immediately after an update, choose Roll Back Driver when available.
- Otherwise, obtain the correct driver from the computer, motherboard, or device manufacturer.
Do not install random x86 or x64 DLLs into System32 or SysWOW64. Outbyte Driver Updater can scan for outdated drivers and show what it finds; driver installation through the full version is optional, and the manufacturer’s driver remains the preferred source.
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Why regsvr32 will not fix this
Do not run:
regsvr32 api-ms-win-core-processthreads-l1-1-1.dll
regsvr32 is intended for specific DLLs that expose registration functions such as DllRegisterServer, commonly used by COM or ActiveX components. An API-set contract is resolved by the Windows loader and is not repaired by registering it.
Likewise, Windows Features will not normally add this contract. Enabling .NET Framework, DirectPlay, Media Features, or another optional component is appropriate only when the application specifically requires that feature and reports it as missing.
If DISM and SFC report no problems
A successful DISM and SFC result means you should shift attention away from Windows file corruption.
Check these points:
- Does only one program fail?
- Did the failure begin after that program updated?
- Is the installed version compatible with your Windows build?
- Is the program 32-bit or 64-bit?
- Is the launcher’s verification tool available?
- Is the application installed from an official source?
- Is a local dependency missing from the application directory?
- Does the program fail under another Windows user profile?
Repair or reinstall the affected application, then contact its publisher with the exact error, Windows version and build, application version, architecture, and installation source.
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When to use System Restore or repair reinstall
Use System Restore when the error began after a recent driver, application, or Windows change and a suitable restore point exists:
- Open Start and search for Create a restore point.
- Open it.
- Select System Restore.
- Choose a restore point dated before the failure.
- Review the affected programs and complete the wizard.
For Windows 11, Microsoft also provides Settings > System > Recovery > Fix problems using Windows Update > Reinstall now on supported systems. This reinstalls the current Windows version while preserving apps, files, and settings. Follow Microsoft’s repair reinstall instructions.
A repair reinstall is justified when multiple applications fail, Windows servicing remains unreliable, and normal DISM/SFC repair has not restored correct operation. Back up important files before any major recovery procedure.
FAQ
Is this a Visual C++ Redistributable file?
No. api-ms-win-core-processthreads-l1-1-1.dll is a Windows API-set contract, not the usual Visual C++ runtime file. Install Microsoft’s Visual C++ Redistributable only when the error specifically names files such as VCRUNTIME140.dll or MSVCP140.dll.
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No. A downloaded copy may contain malware, have the wrong architecture, target a different Windows build, or lack the required exports. It may also hide the real cause, such as an unsupported operating system or broken application installation.
Is the file supposed to be in System32?
There is no single universal physical path, file size, version, or hash for this API-set contract across every Windows edition, architecture, and servicing state. Its .dll ending does not prove that it is an independently replaceable file.
Can Windows 10 or Windows 11 repair every case?
No. DISM and SFC can repair certain Windows component and system-file problems, but they cannot make an application compatible with an unsupported Windows version. If only one program fails after repair, investigate that program.
What information should I give technical support?
Provide the exact error text, Windows edition and build from winver, the affected program and version, whether it is 32-bit or 64-bit, where it was installed from, whether other programs fail, and when the problem began.
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