Modern antivirus software (including Windows Defender) aggressively scans .bin and .exe files while they are being unpacked. It can temporarily lock a file, causing the decompression to fail and triggering Error Code 12.
How to do it:
Note: This does not mean Dodi repacks contain viruses. The compression method triggers false positives due to how it obfuscates code. unarcdll error code 12 dodi repack
Dodi’s installer uses an older decompression engine originally built for Windows 7. Modern Windows versions introduce new security features that can conflict with it.
How to do it:
If you have tried all 7 fixes and still see unarc.dll error code 12:
Sometimes the hard drive you are extracting from or to has bad sectors or permission issues. Note: This does not mean Dodi repacks contain viruses
Antivirus software (Windows Defender, Avast, etc.) sometimes blocks the unarcdll from reading the compressed game files, assuming they are malicious.