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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →customactions.dll is not a standard Windows system DLL. It is a generic filename used by different application installers for code that performs setup, upgrades, service changes, registry work, driver operations, or cleanup.
The safest fix is to identify the program that supplied the file, then repair or reinstall that program using its official installer. Do not download a replacement customactions.dll from a random DLL website.
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Identify the customactions.dll problem first
The filename alone cannot tell you the publisher, version, architecture, or correct replacement. Different products can legitimately contain a file with this name.
Examples include WireGuard for Windows, TortoiseGit, and OpenSC. Their installers use product-specific custom-action DLLs, so a file from one product cannot safely replace the file from another.
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| Evidence | What it usually indicates |
|---|---|
| Error appears while launching one application | That application may have an incomplete installation or missing dependency |
| Error appears during install, uninstall, or upgrade | Windows Installer may be unable to extract or run the product’s custom action |
| Path is under the application folder | The application probably owns the file |
Path is under C:WindowsInstaller*.tmp-* |
An MSI may have extracted the file temporarily |
File is under System32 or SysWOW64 |
Do not assume Windows owns it; verify its signature and related program |
| Error 1721, 1722, or 1723 | The MSI custom action or an operation required by it failed |
| Error 193 or “not designed to run on Windows” | The binary may be corrupt, incompatible, or the wrong architecture |
Before changing anything, record:
- The complete error message
- The full path shown in the error
- The application being launched, installed, removed, or updated
- Whether the problem began after an update, uninstall, restore, cleanup, or antivirus detection
- Whether the affected program is 32-bit, 64-bit, or ARM64
- Your Windows version and the application version
Search for the owning file
Open File Explorer and check the application’s installation directory first. Common locations include C:Program Files, C:Program Files (x86), and a game launcher’s library folder.
You can also search from an elevated Command Prompt:
where /r C: customactions.dll
To open an elevated Command Prompt, select Start, type cmd, right-click Command Prompt, choose Run as administrator, and approve the prompt. A full-drive search can take considerable time.
For a suspected application folder, use PowerShell:
Get-ChildItem "C:Program FilesSuspected App" -Filter customactions.dll -Recurse -ErrorAction SilentlyContinue
Replace C:Program FilesSuspected App with the actual folder.
A filename match is not proof of ownership. Right-click the file, select Properties, and inspect Details and Digital Signatures. Compare the location and publisher with the application named in the error. If the file is inside C:WindowsInstaller or a temporary MSI directory, it may only exist while the original installer is running.
Fix 1: Repair the application that owns the file
This is the most likely solution.
Use Windows’ repair option
- Press Windows + I to open Settings.
- Select Apps.
- Select Installed apps on Windows 11, or Apps & features on Windows 10.
- Find the application named in the error.
- Select the three-dot menu on Windows 11, or select the application on Windows 10.
- Choose Advanced options if available.
- Select Repair.
- Restart Windows and test the application.
Some desktop applications do not expose a Repair button in Settings. In that case:
- Press Windows + R.
- Enter
appwiz.cpl. - Press Enter.
- Select the affected program.
- Choose Change, Repair, or Modify if the installer provides one.
- Complete the wizard, restart Windows, and test again.
Games may instead provide Verify files, Repair, or Scan and repair inside their launcher. Run that function before deleting the game or manually replacing files.
Reinstall from the official source
If repair is unavailable or fails:
- Close the affected application and its launcher.
- Open Settings, select Apps, then Installed apps.
- Uninstall the affected program.
- Restart Windows.
- Download the current installer from the application developer’s official website or the official product launcher.
- Select the correct build for your system: x86, x64, or ARM64 where those choices are offered.
- Right-click the installer and choose Run as administrator.
- Finish the installation and launch the program.
For a product such as TortoiseGit, choose the installer architecture that matches the application you intend to run. WireGuard and other products may publish separate architecture-specific installers. Do not copy a DLL from a different computer, even if the filenames match.
If the application still fails after a clean reinstall, note the exact error, path, architecture, and installer version. The problem may involve a dependency, permissions, security software, or an MSI action rather than the missing file alone.
Fix 2: Troubleshoot MSI errors 1721, 1722, and 1723
Windows Installer custom actions run during installation, upgrade, and removal. Microsoft’s Windows Installer error documentation describes error 1723 as a case where a DLL required to complete the installation could not be run.
If the error includes 1721, 1722, or 1723:
- Cancel the installer.
- Restart Windows.
- Close the application and any launcher associated with it.
- Download a fresh installer from the product’s official source.
- Save it to a local folder such as Downloads rather than running it from a network share.
- Right-click the installer and select Run as administrator.
- Retry the install, upgrade, or removal.
If the failure occurs during an uninstall, first reinstall the same application version if possible. This can restore the installer files required to remove or repair it.
Do not manually copy customactions.dll into C:WindowsInstaller. MSI temporary files are normally extracted and managed by Windows Installer. Manually placing a file there is not a durable repair and may leave the package in an inconsistent state.
If every application installer fails, investigate %TEMP% permissions, Windows Installer, security software, and Windows corruption. If only one product fails, keep the investigation focused on that product.
Fix 3: Check antivirus quarantine
Security software can quarantine or remove an installer DLL. This does not automatically mean the file was malicious, and it does not prove that antivirus caused the error.
Verify the file’s location and publisher before restoring it.
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- Open Windows Security from the Start menu.
- Select Virus & threat protection.
- Select Protection history.
- Look for a quarantined item matching the application or file.
- Expand the item and review its path and detection details.
- Restore it only if the file belongs to the trusted application and the installation source is legitimate.
- Reinstall or update the application if the detection returns.
Microsoft provides further guidance for restoring quarantined files. If the file’s publisher cannot be verified, do not restore it. Obtain a clean copy by reinstalling the identified program from its official source.
Fix 4: Check architecture and application runtimes
A 32-bit application on 64-bit Windows generally needs the x86 runtime, not only the x64 runtime. ARM64 applications require the appropriate ARM64 build where supported.
First identify the application architecture from its documentation, installer choices, or product support page. Then reinstall the matching application build.
Only install Visual C++ when the identified program requires it or its installer reports a missing runtime. customactions.dll itself is not a Visual C++ runtime DLL.
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Microsoft’s latest supported Visual C++ Redistributable page provides the official packages:
Install the architecture required by the application, restart Windows, and test again. Older software may require an older side-by-side runtime, including Visual C++ 2013 or an earlier release. Follow the application vendor’s requirement rather than installing runtimes at random.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Fix 5: Repair Windows components when Windows corruption is suspected
System repair commands are useful when Windows components, protected system files, or system servicing are damaged. They normally will not recreate a third-party application’s missing customactions.dll.
- Open Start.
- Type
cmd. - Right-click Command Prompt.
- Select Run as administrator.
- Run:
DISM.exe /Online /Cleanup-Image /RestoreHealth
- Wait for it to finish.
- Then run:
sfc /scannow
- Restart Windows after both commands complete.
- Retry the affected application or installer.
Microsoft documents DISM image repair and System File Checker as Windows component repair tools. If SFC reports that it repaired files, test the original application again. If it reports that it could not repair everything, run Windows Update, restart, and repeat the investigation rather than assuming the third-party DLL was restored.
Repeatedly hunting through repair commands without knowing what changed is inefficient; Outbyte PC Repair can scan for system problems and show what it finds, while the repair is performed by the full version. It is optional, and reinstalling the application that owns customactions.dll remains the definitive fix for an application-specific file.
Fix 6: Update drivers only when the error identifies a driver-related product
Most customactions.dll errors do not require a driver update. Consider drivers only when the failing installer is for hardware, a VPN, a security product, a printer, or another program that explicitly reports a driver installation failure.
To update a driver manually:
- Right-click Start.
- Select Device Manager.
- Expand the category related to the affected hardware.
- Right-click the device.
- Select Update driver.
- Choose Search automatically for drivers.
- Restart Windows if prompted.
- Retry the original application installer.
For a vendor-supplied driver, download it from the hardware manufacturer’s official support page and select the correct Windows architecture. Do not use a driver update to replace an application’s custom-action DLL.
Manually checking hardware entries and matching driver packages can take time when several devices are involved; Outbyte Driver Updater can scan and identify outdated drivers, while driver installation is handled by the full version. It is optional and does not replace reinstalling the specific application that supplied customactions.dll.
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Do not download a universal DLL replacement
There is no universal customactions.dll download that fits every Windows computer. A random copy may contain the wrong product code, architecture, dependencies, or malicious modifications. It may also hide the real issue: a damaged MSI, incomplete update, quarantine event, or failed uninstall.
Use the identified application’s official installer instead.
Do not copy the file into System32 or SysWOW64
Copying a file into C:WindowsSystem32, C:WindowsSysWOW64, or an application folder can create a second problem. Windows may load the wrong binary, and the installer may still be unable to locate the file it expects.
Do not routinely run regsvr32
regsvr32 is for DLLs that expose the COM DllRegisterServer mechanism. Installer custom-action DLLs are generally called through exported installer action functions, not COM registration.
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If reinstalling still fails
Collect the following before contacting the application vendor:
- Full error text and error code
- Complete file path
- Application name and version
- Windows version
- x86, x64, or ARM64 architecture
- Whether the failure occurs during launch, install, upgrade, or uninstall
- Antivirus detection or quarantine details
- The MSI log, if the installer creates one
- The exact custom-action name shown in the log
If only one product fails, report it to that product’s developer. If every MSI fails, investigate Windows Installer service issues, %TEMP% permissions, security software, and system corruption.
FAQ
Is customactions.dll part of Windows?
No single standardized Windows component owns this basename. It is used by unrelated application installers.
Can I replace it with a file from another computer?
Not safely. The other computer may have a different product, architecture, version, or dependency set.
Should I install Visual C++?
Only when the owning application requires it or reports a missing runtime. Match x86, x64, or ARM64 to the application.
What does error 1723 mean?
It indicates that a DLL required for the Windows Installer operation could not be run. Repair or reinstall the product whose MSI produced the error.
Will SFC fix the missing file?
Usually not. SFC repairs protected Windows files, while customactions.dll is normally supplied by a third-party application.
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Is the file malware?
The filename alone cannot establish that. Check the path, digital signature, application ownership, and antivirus history before restoring or trusting it.
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