How about using Sync. https://support.mozilla.org/en-US/kb/sync-logins-firefox-desktop

If I'm understanding Sync correctly, I would have to sync with another installation of Firefox that's using my profile. But I installed over the previous Linux distro and its version of Firefox. Also, given a choice, I'd rather not put my profile in the cloud, even briefly.

My current distro is likely to upgrade its Firefox version within days, which would solve the problem. However, I'd rather not wait, and the previous distro was getting too buggy for me to want to reinstall it.

This is solved now that I've switched to a Linux distro that has the same version of Firefox. (This wasn't the only reason I switched again.) The next time I distro hop, I will know to compare Firefox versions and, if necessary, hold off on upgrading my current Firefox installation until the versions are the same. (A slight difference beyond the decimal point didn't matter.)

You can always just run a separate copy of Firefox. I was losing tabs many months ago witch is why I run Nightly, but also still run distro, 78 ESR, and 91. They are like backups of my tabs and bookmarks in case 1 dies.

What distro did you switch to? Don't forget to mark your comments as resolved.

I'm currently on Fedora; not sure if I'm staying there. I can see from your username and picture that you're on openSUSE. The problem happened on openSUSE Tumbleweed, which I had chosen in part because it holds new packages for testing. So my choice essentially created the problem.

I was running from another distro that was causing me problems (Manjaro), rather than seeing a clear migration path. So if Fedora allows me to get things done without huge problems, I'll be able to take more time to explore my options, including Tumbleweed with a different desktop environment.

Thanks for your suggestions!

I'm running openSUSE Tumbleweed. ;-)) You should run more than 1 version of Firefox. Sync will see the other version as another device and you can have a backup of tabs and bookmarks.

Note that installs.ini stores references to the installation path. Each distro likely has its own installation path and if Firefox notices that the path of the binary that last used this profile is different then Firefox refuses to use this profile. This path to the last used version is stored compatibility.ini in the profile folder and removing this file makes it possible to circumvent this block.

See "Blocking downgrades" and "Disabling the changes".

• https://support.mozilla.org/en-US/kb/understanding-depth-profile-installation

Thanks for the added information, cor-el. However, doesn't the article you linked to suggest that circumventing the block may cause problems? That's why I was first asking if there had been any changes to the structure of the profile between the 2 versions in question.

This turned out to be a short-lived problem. FIrst, it went away when I switched to another Linux distro that had the same version. Then, when I returned to the distro where the problem returned, Firefox had finally been upgraded. (Yes, jonzn4SUSE, I am back on openSUSE Tumbleweed, in a different desktop environment this time.) if at all possible, I plan to stay with this distro for a while. And even if I do switch yet again, Tumbleweed doesn't upgrade to the latest version of Firefox right away, so it's unlikely that I'd be switching to a distro with an even earlier version of Firefox.