The unarc.dll file handles decompression. Error code 11 specifically indicates:

If none of the above works, you may have faulty physical RAM.

If the installer uses FreeArc + InnoSetup (common for repacks), you can bypass unarc.dll entirely:

Then manually run any post-install scripts (registry, redistributables).

Windows 11 may run out of "virtual address space" when extracting large archives.

  • Click Set → OK → Restart your PC.

    • Note: Use higher values (e.g., 16 GB max) if you have less than 8 GB of physical RAM.

    Unarc.dll Returned An Error Code 11 Windows 11

    The unarc.dll file handles decompression. Error code 11 specifically indicates:

    If none of the above works, you may have faulty physical RAM.

    If the installer uses FreeArc + InnoSetup (common for repacks), you can bypass unarc.dll entirely:

    Then manually run any post-install scripts (registry, redistributables).

    Windows 11 may run out of "virtual address space" when extracting large archives.

  • Click Set → OK → Restart your PC.

    • Note: Use higher values (e.g., 16 GB max) if you have less than 8 GB of physical RAM.