Follow these solutions in order, as they are arranged from the most likely to fix the issue to the more advanced.
Sometimes, the file actually is corrupt. If you used BitTorrent, your client might have saved incomplete pieces.
Restart and try the installation again, then revert the setting afterward. Clear Temporary Files , and delete all files in the folder. Repeat for Update Essential Runtimes : Ensure you have the latest Microsoft Visual C++ Redistributables installed. Compatibility Mode : Right-click the installer, go to Properties > Compatibility , and run it in compatibility mode for how to fix unarcdll returned an error code14 upd
If the system's core dynamic link libraries are corrupted, Windows will fail to register the extraction commands accurately.
The (often appearing alongside ISDone.dll ) typically occurs during the installation of highly compressed games or software repacks. It indicates a decompression failure , usually caused by corrupted installation files, insufficient memory (RAM/Virtual Memory), or hardware overheating during the intensive unpacking process. Immediate Fixes Follow these solutions in order, as they are
Open your client (e.g., qBittorrent), right-click the game package download, and select Force Recheck or Verify Local Files . This scans the data block-by-block and automatically redownloads any corrupted segments.
Accumulated junk files inside Windows cache directories frequently cause memory collisions during the high-speed decompression processes managed by unarc.dll . Press to open the Run box. Type temp and hit Enter . Restart and try the installation again, then revert
Also add your game installation folder AND the temp folder ( %temp% ) to your antivirus exclusions list before re-enabling.