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ace_clipboard.dll is an Arma 3 extension installed by the ACE3 realism mod. It is not a Windows system DLL, Visual C++ component, DirectX file, or .NET file.
The safest fix is to repair or reinstall ACE3 through its official Steam Workshop distribution, make sure CBA_A3 is installed and enabled, and confirm that Arma 3 is loading the correct 32-bit or 64-bit extension. Do not copy this file into System32, register it with regsvr32, or download a replacement from a random DLL site.
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What ace_clipboard.dll is
ACE3 uses the extension for clipboard-related operations, including importing and exporting ACE settings and loadouts. The ACE3 project contains both:
| File | Expected use |
|---|---|
ace_clipboard.dll |
32-bit Arma 3 executable |
ace_clipboard_x64.dll |
64-bit Arma 3 executable |
ACE3 normally loads the file through Arma 3’s extension system. A working log can contain a message similar to:
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CallExtension loaded: ace_clipboard (...ace_clipboard_x64.dll)
The file should normally be under the ACE3 mod directory, often a path resembling:
C:Program Files (x86)SteamsteamappscommonArma 3.Workshop@ace
A manually installed copy may instead be under:
C:Program Files (x86)SteamsteamappscommonArma 3@ace
The exact folder can differ. The important point is that it belongs inside the ACE3 installation used by Arma 3, not in a Windows system folder.
Start with the official ACE3 repair
This fixes the most common causes: an incomplete Workshop download, a stale mod copy, a disabled mod, or an update that did not finish.
- Close Arma 3 and the Arma 3 launcher.
- Open Steam and select Library.
- Open Arma 3’s Workshop page.
- Check that ACE3 is subscribed and that Steam has finished downloading it.
- If Workshop synchronization is clearly stuck, unsubscribe from ACE3, restart Steam, then subscribe again.
- Allow the complete download to finish.
- In Steam, open Arma 3 and select Play.
- Open the launcher’s Mods section.
- Enable both
CBA_A3andace. - Start the game and test in the editor.
ACE3 requires CBA_A3. If CBA_A3 is missing, disabled, outdated, or duplicated by an old manual installation, ACE3 may fail even when ace_clipboard.dll is visible on disk.
If you installed ACE3 manually, remove or move the old @ace folder before installing the official current release. Multiple ACE3 copies can make the launcher load a different extension from the one you inspected.
How to tell whether this worked
The error is resolved when Arma 3 starts without:
[ACE] (common) ERROR: Extension ace_clipboard.dll not installed.
The RPT log should show that the extension loaded, or the ACE3 clipboard-related feature should work in the editor. If the file exists but the same message remains, continue with the architecture and security checks below.
Check the Arma 3 architecture
A file can be present and still fail because the executable is using the wrong architecture.
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ace_clipboard_x64.dll
A 32-bit executable requires:
ace_clipboard.dll
Architecture-related logs may contain wording such as:
x32 Trying to load a x64 dll 'ace_clipboard.dll' from a 32-bit executable
or:
x64 Trying to load a x86 dll 'ace_clipboard_x64.dll' from a 64-bit executable
Do not rename one file to imitate the other. Instead:
- Close the game.
- Update ACE3 through Steam Workshop.
- Remove stale manual ACE3 files if both Workshop and manual copies exist.
- Launch the supported 64-bit Arma 3 executable where applicable.
- Test again with only the current
aceandCBA_A3entries enabled.
If you use Wine or Proton, check the compatibility layer’s architecture and the exact executable being launched. A Windows DLL copied into a Linux dedicated server will not automatically work there.
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Check whether antivirus quarantined the file
A security product may remove or block an ACE3 extension after a scan or mod update. Do not assume that every detection is a false positive, but do not assume that a BattlEye or antivirus warning proves the file is malicious either.
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- Open Windows Security.
- Select Virus & threat protection.
- Select Protection history.
- Look for an event naming
ace_clipboard.dll. - Check the complete file path and action taken.
- Compare the path with the ACE3 folder used by the Arma 3 launcher.
- Update Microsoft Defender or your antivirus definitions.
- Rescan the official ACE3 installation.
- Restore or allow the file only when it came from the official ACE3 distribution and the installation is trustworthy.
- Repair or redownload ACE3 if the file was altered, damaged, or deleted.
If the file keeps triggering detection, submit it to the security vendor for review rather than downloading an unrelated copy. A filename match is not proof that a replacement DLL is safe.
Diagnose a BattlEye block
BattlEye logs may show:
Blocked loading of file '...Arma 3@aceace_clipboard.dll'
That message means BattlEye blocked a file the game attempted to load. It does not, by itself, prove that the file is malware or that you have been banned.
Use this order:
- Confirm that the file came from ACE3’s official Workshop distribution or official release.
- Update Arma 3, ACE3, CBA_A3, and BattlEye.
- In Steam, right-click Arma 3 and select Properties.
- Open Installed Files.
- Select Verify integrity of game files.
- Review Windows Security and any third-party antivirus history.
- Check the BattlEye log and Arma 3 RPT log for the full path and preceding error.
- Test in an offline or BattlEye-disabled environment only as a diagnostic step where appropriate.
Do not permanently disable BattlEye to make the error disappear, particularly when joining protected servers. If a current, legitimate ACE3 file continues to be blocked, provide the full path and logs to the appropriate BattlEye or ACE3 support channel.
Verify Arma 3 files through Steam
Steam verification is useful when several Arma 3 files are missing, Workshop content appears incomplete, or antivirus removed files.
- Open Steam.
- Select Library.
- Right-click Arma 3.
- Choose Properties.
- Select Installed Files.
- Click Verify integrity of game files.
- Wait for the process to finish.
- Restart Steam and allow any pending Workshop downloads to complete.
- Recheck the Arma 3 launcher’s Mods list.
Verification repairs the Arma 3 installation. It may not fully repair a separate Workshop mod, so reinstall ACE3 and CBA_A3 if the mod folders remain incomplete.
Reinstall ACE3 and CBA_A3 together
Use this step when several ACE3 extensions fail, the problem began after an update, or the launcher shows duplicated or mismatched mod entries.
- Close Arma 3 and Steam.
- In Steam Workshop, unsubscribe from ACE3 and CBA_A3.
- Exit and reopen Steam.
- Subscribe to CBA_A3 first, then ACE3.
- Wait for both downloads to finish.
- Open the Arma 3 launcher.
- Enable only the current
CBA_A3andaceentries. - Temporarily disable duplicate, manually installed, or older ACE-related entries.
- Test in the editor before re-enabling other mods.
Do not download ace_clipboard.dll as a standalone file. ACE3 is the relevant package, and the correct extension must match its release, Arma 3 architecture, and platform.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsRepair Windows components only when other symptoms support it
SFC and DISM do not normally restore ACE3 files. They repair Windows components, so use them only if unrelated programs also fail, Windows reports system corruption, or broader system-integrity errors are present.
Open Command Prompt as administrator:
- Open Start.
- Type
Command Prompt. - Right-click it.
- Select Run as administrator.
- Run:
DISM.exe /Online /Cleanup-Image /RestoreHealth
- When it completes, run:
sfc /scannow
- Restart Windows and test Arma 3 again.
Microsoft recommends running DISM before SFC. If both commands report no problems but ACE3 still cannot load, return to the ACE3 installation, architecture, antivirus, and BattlEye checks.
Manually hunting through Windows repair output and repeating SFC or DISM without knowing what changed can be time-consuming. Outbyte PC Repair offers a free scan that shows detected issues, while repair features require the full version; for this file, reinstalling ACE3 remains the definitive fix.
Do not update drivers unless there is a separate driver problem
Graphics, sound, and chipset drivers do not normally provide ace_clipboard.dll. Device Manager is relevant only if Arma 3 has additional hardware or graphics failures.
To check for a driver issue:
- Right-click Start.
- Select Device Manager.
- Expand the device category related to the separate error.
- Right-click the device.
- Select Update driver.
- Choose Search automatically for drivers.
- Restart Windows if a driver is installed.
Do not reinstall drivers merely because ACE3 reports a missing extension. If you are already diagnosing several driver failures, Outbyte Driver Updater can scan for outdated devices; its free scan identifies issues, while driver installation through the full version is optional. It does not replace the ACE3 repair required here.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Linux server and Proton exceptions
A Linux dedicated server may report the Windows .dll extension as unavailable because the required native Linux extension is absent or incompatible. That is not repaired by copying the Windows file into a Linux system directory.
For Linux, Wine, or Proton:
- Identify whether the error occurs on the dedicated server or the Windows client.
- Record the platform and compatibility layer.
- Check whether the server requires a native extension.
- Confirm the architecture reported by the log.
- Do not use Windows
System32orSysWOW64assumptions on a Linux server. - Do not mix Windows and Linux ACE3 extension files.
A Windows player client and a dedicated server may not need identical extension arrangements. Diagnose each side separately.
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What not to do
Do not copy the file to System32 or SysWOW64
ace_clipboard.dll is an ACE3 game extension, not a shared Windows component. Copying it into either system directory does not make Arma 3 load the correct mod copy and can create confusing version conflicts.
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Do not use regsvr32
Arma 3 loads ACE3 through its extension mechanism. It is not a normal COM or ActiveX component that should be registered in Windows.
This command is not an appropriate repair:
regsvr32 ace_clipboard.dll
A registration or entry-point error from that command is irrelevant to the ACE3 problem.
Do not install Visual C++, DirectX, or .NET as a guess
Those components are not the standard solution for this specific ACE3 extension. Install a runtime only when an Arma 3 or ACE3 log explicitly identifies that dependency.
Do not use a generic DLL download site
Random DLL sites can provide malware, the wrong architecture, an incompatible build, or a modified file. They also leave the underlying ACE3, CBA_A3, Workshop, antivirus, or BattlEye problem unresolved.
If the error remains, collect these details
Before reinstalling Windows or changing unrelated drivers, record:
- The exact error text.
- Whether the file is absent or present.
- The full ACE3 path being loaded.
- Whether Arma 3 is using 32-bit or 64-bit mode.
- Windows, Linux, Wine, or Proton platform.
- ACE3 and CBA_A3 installation method.
- Whether duplicate
@acefolders exist. - The relevant Arma 3 RPT log lines.
- Any BattlEye block message.
- Any antivirus quarantine event.
- Whether other ACE3 native extensions fail too.
A message saying “not installed” does not always mean the file is absent. It can also indicate a wrong architecture, blocked file, incorrect mod path, incompatible platform, permissions problem, or incomplete update.
FAQ
Is ace_clipboard.dll a Windows file?
No. It is an ACE3 extension for Arma 3.
Where should it be?
Inside the ACE3 mod directory used by Arma 3, commonly under @ace in the Arma 3 installation or Workshop content path.
Should I download it separately?
No. Repair or reinstall the complete ACE3 mod from its official distribution.
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The wrong copy may be loaded, the architecture may not match, antivirus or BattlEye may be blocking it, or the file may be incompatible with the platform.
Which file does 64-bit Arma 3 use?
The 64-bit form is ace_clipboard_x64.dll. Do not rename it or substitute it for the 32-bit file.
Do I need CBA_A3?
Yes. ACE3 requires CBA_A3, and both should be current and enabled in the Arma 3 launcher.
Can SFC repair it?
No. SFC and DISM repair Windows components, not the ACE3 mod. Use them only when separate evidence points to Windows corruption.
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