If the archive itself is broken, no amount of system tweaking will fix it. A single missing byte can trigger Error Code -6.
Type in the Windows search bar and press Enter.
If you are trying to install a (downloaded from a repack or a cracked setup) and you suddenly face the dreaded pop-up: "Unarc.dll Returned an Error Code -6" , you are not alone.
Many users skip this basic step, yet it resolves the error instantly.
If the installer isn't the problem, your hard drive might be. A failing drive can corrupt files during extraction. To check, use Windows' built-in tool:
If your setup archive was corrupted during the initial download, it will consistently trigger Error -6. Press Windows Key + R to open the Run dialog box. Type %temp% and press .
Type into the Windows search bar, right-click Command Prompt , and select Run as administrator .
Fixing Unarc.dll Errors in Game Installs | PDF | Malware - Scribd