"Another program on your computer would like to modify Firefox with the following add-on"
I have version 13, and I am running an Intel Mac Mini with Mac OS X v10.6.8. For the past month I have noticed that sometimes Firefox will start up with no add-ons enabled, and when I look at them in the add-ons section, there'll be nothing there. I then go to get a new add-on, install it, and then restart it and I get a gazillion tabs for each of the add-ons I had installed, all bearing this same message: "Another program on your computer would like to modify Firefox with the following add-on"
I don't know why I am getting this message and I don't know how to fix it. I do not have any anti-virus software installed. Starting Firefox in safe mode does not help at all, as even there it does not detect that there are any add-ons installed at all.
Alle svar (2)
try to delete/rename the following files, which store information about your extensions & might have gotten corrupted, if present in your profile folder (you can access it in firefox > help > troubleshooting information): extensions.ini, extensions.cache, extensions.rdf, extensions.sqlite & extensions.sqlite-journal (they will be regenerated the next time you launch firefox).
also refer to https://support.mozilla.org/en-US/kb/Unable%20to%20install%20add-ons#w_co...