If that file is missing, the safest solution is to reinstall IDM from the official website. Common Troubleshooting
If you switch from Chrome to Firefox, you will need idmmzcc2.xpi , not idmgcext.crx . idmgcext.crx
Some aggressive antivirus programs may flag the genuine idmgcext.crx as a "Potentially Unwanted Program" (PUP) because it modifies browser behavior (intercepts network requests). This is a false positive. You can safely add an exception for IDM’s folder. If that file is missing, the safest solution