Firefox Community Forum

Keep getting error message that "cannot open firefox because a copy if already open. Only one copy can be open at a time." And there is NO firefox app open. I tried deleting the app and re downloading/installing again, but that didn't work.

Help and suggestions please?

got stupid "helper tool" pop-up so trashed old version, downloaded fresh copy of 12/30/24 version for MACOS and installed under my admin user...works great, no problem.

Switched to non-admin user on same machine and FF never opens, icon just keeps bouncing and I have to force close.

I'm trying to use a script which requires a question mark after the "dot com." I.e., if the url should be http://www.URL.com?custom_URL, it changes it to http://www.URL.com/?custom_URL. How to I keep it from changing the URL - and what is the point of jamming that slash in there in the first place?

I have been building websites on and off for many years using Notepad++, HTML, CSS, JavaScript, and PHP. During development and maintenance, I heavily use Firefox and Firefox Developer Edition on the computer where I build the sites (both editions are affected). I also have many notes on an offline website.

Recently, the links in these offline websites no longer work in Firefox. They function as usual in Microsoft Edge and the newly installed Vivaldi 7. They also work on an old laptop with an older version of Firefox. I think the issue was introduced in one of the recent updates. Could you please look into this? Otherwise, I cannot use Firefox as an offline browser and the developers add-ons on my laptop anymore.

Kind regards, Martijn de Jong

I sent this message to Mozilla support in Dutch and would like to send an English translation as well.

Do you have a solution for this issue?

Firefox will not start up after latest update earlier this week. Troubleshoot mode or refresh does not work either. Clearing caches, restarting does not work either. Worked great before latest update.