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Former Member's avatar
Former Member
3 years ago

Firefox add-on failed to install - cannot modify the needed file

When I try to install the Firefox 1Password add-on on a Mac I get the error: "about:addons 1Password - Password Manager could not be installed because Firefox cannot modify the needed file."

I also tried to download the add-on and install from the file by using:

Firefox -> Preferences -> Extensions and Themes -> Click the Gear -> Install the add-on from File
and point to the downloaded .xpi file. This gives me the same error.

Thank you!


1Password Version: Not Provided
Extension Version: Not Provided
OS Version: macOS Monterey 12.5
Browser:_ Firefox
Referrer: forum-search:cannot modify the needed file

  • Former Member's avatar
    Former Member

    Hi andrew, thank you for responding. Yes, I am using that link and yes, the issue persists even in Troubleshoot mode. In case it is helpful, I had the same problem with the plugin for Keeper. However, I read on a support site that I had to download the xpi file and manually load it which worked for Keeper. I have not been able to get the 1Password addon to load for 1Password. ( i tried Keeper and didn't like it - that is why I downloaded 1Password ).

  • Former Member's avatar
    Former Member

    Success after Refresh Firefox!

  • @keithhag

    Sounds great and thank you for letting us know. You mentioned 12.5 in your introduction. I would recommend considering an update of macOS to 12.6.3, at your convenience.