HI, What you're explaining seems to suggest that your firefox was installed onto said drive. This means that the drive will have to be connected in order to run firefox. In the same way you store a movie on a Hard drive and unplug the drive while watching it will stop the playback as its source is disconnected. The solution to this would be to uninstall firefox ( make sure you save your settings and sync everything before uninstalling in order to avoid losing any data ) with the external drive connected , then disconnect your drive and redownload and install the latest version of Firefox from mozilla's website. Regards Tintin P.S. This was posted in the iOS section of the forums, in the future use the Desktop Browser/Mac browser tag