Setting your Windows Power Plan to and capping the Maximum processor state at 99% in advanced power settings.
Reducing the number of active processors to 6 or 8 in msconfig > > Advanced Options . how to fix unarc.dll error code 12
Background software can conflict.
Bad sectors on your hard drive or SSD can corrupt data during extraction. Setting your Windows Power Plan to and capping
Use MemTest86 (more thorough) via USB.
Since corruption is the #1 cause:
By systematically working through these steps, you should be able to bypass the unarc.dll error code 12 and complete your installation. Most users find that increasing Virtual Memory or disabling their antivirus provides an immediate fix. how to fix unarc.dll error code 12