I tried installing it from the addon site (with it already installed) and it didn't work. I then tried uninstalling it and adding it back, restarting FF and giving it another go, but still doesn't work. Not sure what's blocking it, but I installed it on another machine and it works, so it must be something with my main rig Every time I try to install the addon Firefox gives me an error message "The addon download from this site could not be add to Firefox because it appears to be corrupt". Its been doing this for several months now. Chrome works fine - have added it on several new PCs recently. Thanks
I didn't find the right solution from the Internet.
markblake replied
423 weeks ago