The Adobe Acrobat Add-On Extension for Firefox was missing so I attempted to add it from Adobe Acrobat Pro 2017. I have had to do this manually by installing from the adobe_acrobat-1.0-windows.xpi file. This usually has worked. When i tried to add it this time is said the add-on file was corrupt. I tried uninstalling and redownlading AdobeAcrobatPro 2017 thinking this would add an uncorrupted file and got the same the same message. Unfortunately, because I had used the Adobe license key too many times for Acrobat 2017 on my computer I had to upgrade to Adobe Acrobat Pro 2020. i had hoped this would solve the problem. But no, I get the same message corrupt file message even with a new copy of the Acrobat Pro 2020. What is going on? Can anyone help with this?