Firefox 67 breaks shared profile between Ubuntu and Windows10
Hi,
I use Firefox on a Windows 10/Ubuntu 18.04 dual boot system and share the profile of the Windows partition to use the same Firefox information with both installations. After upgrading the Firefox Win10 version to 67.0, I get the error message uploaded as a picture. The Ubuntu Firefox version is also 67.0, so there is no older version that modifies the profile information.
I found this thread https://support.mozilla.org/en-US/questions/1259820 describing a similar question, and the chosen solution to delete the compatibility.ini from the profile folder revived the profile. However, this is not a permanent solution. Using Ubuntu Firefox after Windows Firefox is unproblematic, whereas the error reappears in Windows Firefox after using Ubuntu Firefox. I have to delete now the compatibility.ini every time I use Windows Firefox after Ubuntu Firefox, which is rather annoying. Obviously, the Ubuntu and the Windows version of Firefox 67 interpret this .ini file differently. Is there anything planned to synchronize both versions of Firefox 67 better? Or any other solution that solves this problem permanently? And no - I don't want to store my profile information on an external Sync server. Thank you for your time reading this. Any help is much appreciated.
Chosen solution
I think that this is how it works:
The compatibility.ini file stores the path to the Firefox version that last used this profile. Firefox 67 uses installs.ini to map a specific Firefox installation folder to a specific profile and lock this profile, so it can't be used by other Firefox versions. If the path in compatibility.ini and installs.ini are different then Firefox will refuse to use the profile as long as the profile is locked. Deleting compatibility.ini makes it impossible to check this and Firefox allows to use this profile. Sharing a profile between platforms is not recommended because files like pkcs11.txt and prefs.js contain a path to the current profile folder.
You can use a script file (Bash on Linux and CMD on Windows) to remove this file. I don't know if this works when done automatically via an autoconfig.cfg file.
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Chosen Solution
I think that this is how it works:
The compatibility.ini file stores the path to the Firefox version that last used this profile. Firefox 67 uses installs.ini to map a specific Firefox installation folder to a specific profile and lock this profile, so it can't be used by other Firefox versions. If the path in compatibility.ini and installs.ini are different then Firefox will refuse to use the profile as long as the profile is locked. Deleting compatibility.ini makes it impossible to check this and Firefox allows to use this profile. Sharing a profile between platforms is not recommended because files like pkcs11.txt and prefs.js contain a path to the current profile folder.
You can use a script file (Bash on Linux and CMD on Windows) to remove this file. I don't know if this works when done automatically via an autoconfig.cfg file.
Thank you for the explanation and your suggestion. I assume it will be helpful for people more experienced than me. I don't feel particularly adventurous writing a CMD file and destroying my Win partition or deleting unintentionally files with this script file.
It is also still not clear to me, why this problem appears when switching from Linux to Win10 but not the other way round. According to your explanation, shouldn't it be present in both situations?
Turns out it was possible even with my restricted knowledge. This StackOverflow answer contains the path, where I stored the .cmd file, and I changed the content of this file to the directory of my shared Firefox profile to delete the compatibility.ini on startup. So, if I can do it, everybody can do it. Thanks again for the suggestion.