Sharing a Firefox or Thiunderbird profile for dual boot

[SiliconWizard]

Just wondering if anyone has done that and if they see any potential issue with this.

The idea is to share your Firefox and/or Thunderbird profile in a dual-boot system. (On a partition that can be accessed in R/W by both OSs.)

I have already copied profiles back and forth between Windows and Linux without any apparent problem, so sharing them this way (as long as there is no concurrent access, which there won't be in a dual-boot arrangement) should be fine, but just making sure. That would allow working in either OS with no disruption regarding your web browsing and email.

[pcprogrammer]

Not between a linux and windows dual boot, but with linux version x and linux version y, and have no problems with that.

But you do have to set it up such that they are in a dedicated location and not in your home directory, at least for linux the two home directories can not be the same. That is how I tried it at first, but gave all sorts of problems with linux itself. Was between two versions of Ubuntu. Had to redo the setup.

[SiliconWizard]

But you do have to set it up such that they are in a dedicated location and not in your home directory, at least for linux the two home directories can not be the same.

Yep obviously. Yes by default Firefox expects profiles to be in your 'home directory', same on Windows.
I think you can make Firefox/Thunderbird use a profile in a different directory, but good point, that's certainly something to consider.

[Nominal Animal]

Long time ago, in the era of the first Linux netbooks (Acer Aspire One A110L in particular), I used a script to extract my Firefox profile (including small caches) to a small 64-megabyte ramdisk (tmpfs) whenever the first Firefox instance was started, for much improved usability.  When the last Firefox instance exited, the profile would be re-archived (tar'ed, no compression), to maintain all updates.  This worked perfectly.

I first tried to trigger it from my greeter (GDM, so that the profile would be extracted on Linux login, and recompressed at logout/shutdown), but its session script support was FUBAR, and the Gnome devs didn't really care.

So, if the same profile works fine on Windows and Linux, you only need to worry about copying the profile –– both TO and FROM –– when there is NO applcation using that profile.  I don't know how you'd ensure that in Windows (other than doing it all from the Linux side in a dual-boot system), but it is the one gotcha I had to resolve somehow.  (And by replacing the Firefox startup script, it was rather simple.  The only 'trick' was leaving the parent script wait for the Firefox binary to exit, and then check if the same user had other Firefox instances running, to decide whether to re-archive the profile.  I did mount the tmpfs over the profile directory (xxxxxxxx.default/), too, so it was exactly in the same place it would have been on an ordinary installation.  The archive was in the parent directory, in the same directory you find 'profiles.ini' in.)

As to whether the profile is supposed to be the same wrt. Linux vs. Windows, only the devs really know, I suppose.  Considering both of them are mostly XUL and JS, I would kinda-sorta expect them to be compatible (assuming both are AMD64, i.e. 64-bit x86-64).

[SiliconWizard]

If the profiles absolutely have to sit in your home directory on each platform, obviously you won't be able to share the directory between OSs and will have to copy back and forth. Something I have done successfully in the past. Just a bit tedious.

My thought is that it should be possible to make Firefox/Thunderbird point to an arbitrary profile directory rather than one absolutely sitting in your home directory. I'll just have to check that.

[Nominal Animal]

My thought is that it should be possible to make Firefox/Thunderbird point to an arbitrary profile directory rather than one absolutely sitting in your home directory.

Path attribute in profiles.ini is the absolute path (or relative path if IsRelative=1) to that particular profile.  Works fine in Linux, but I'd be wary of it in Windows (because \ vs \\ vs / separator issues).

[SiliconWizard]

My thought is that it should be possible to make Firefox/Thunderbird point to an arbitrary profile directory rather than one absolutely sitting in your home directory.

Path attribute in profiles.ini is the absolute path (or relative path if IsRelative=1) to that particular profile.  Works fine in Linux, but I'd be wary of it in Windows (because \ vs \\ vs / separator issues).

There it is. By default Firefox sets a relative path:

IsRelative=1
Path=Profiles/xxx.default

Same on Windows and Linux.
I'll try with absolute paths.

[Nominal Animal]

It might be more robust in the medium to long term, if you used a relative path (../../mnt/Win/something/.../foobar.default) to the profile.

While absolute paths work now, it relies on Firefox and Thunderbird developers not changing the default and deprecating IsRelative in the future.  It would not be unprecedented.

[SiliconWizard]

It might be more robust in the medium to long term, if you used a relative path (../../mnt/Win/something/.../foobar.default) to the profile.

While absolute paths work now, it relies on Firefox and Thunderbird developers not changing the default and deprecating IsRelative in the future.  It would not be unprecedented.

I guess that if they ever change that, the fix will be pretty simple, but fair point. I'll keep it relative.

[Ed.Kloonk]

If you're going to fiddle with tbird, consider using https://www.betterbird.eu/