If you’re experiencing a “Unarc.dll error code 11” message, the problem could be caused by the Unarc DLL. If the file is missing, you need to reinstall it. Reinstalling the file is the easiest and most common solution. However, there are times when you need to manually download the file. If you cannot find it, try locating the file on the Unarc website.
Once you have the DLL file, you can try to re-register it with a dll re-registration tool. Make sure to unpack it with the use of a file archiver. If you cannot do this, you can download a third-party program to fix the error. It may be worth it to try. If the error still persists, try a registry cleaner or scan tool.