Hi Karma, does Firefox run normally on the Ubuntu system right now, before making any radical changes? Please confirm that first.

Next, we're going to become familiar with the About Profiles page. If you type or paste about:profiles in the address bar and press Enter/Return to load it, Firefox should display a list of currently known profiles.

Please don't remove anything.

The profile that Firefox is currently using will have this:

This is the profile in use and it cannot be deleted.

If you look at the Root Directory path, you can see where Firefox wants profile folders to be stored.

On Windows, that is similar to:

C:\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles\

On Linux, it might be similar to:

~/.mozilla/firefox/

Note that AppData on Windows and .mozilla on Linux are hidden by default and you may need to set your file explorer to show hidden files and folders in order to access those folders easily.

Fortunately, the About Profiles page has a button to open the listed directory. So you can click that, navigate "up" a level to its parent folder, and then drop in the old profile folder alongside it.

** Is this making sense on your system so far? If not, please pause until a Linux person can advise. **

Once you've pasted the old folder alongside the current one:

Make a note of your migrated profile name -- the part after the dot. For example, if your profile folder name is z1xw45tt.default-release then the profile name would be default-release (sometimes it may be quite long). For best results, we'll re-use that identical name. If we change the name, some of the old profile data may not map correctly leading to missing data.

On the about:profiles page:

• Click the "Create a New Profile" button, then click Next.
• Assign the same name as your migrated profile and Firefox should show a proposed folder name with a new random part (the part before the dot).
• Click the "Choose Folder..." button and select the old profile folder you pasted so that Firefox picks up the full old name (the part before the dot and after the dot).
• Back in Firefox, click the Done button.

After creating a new profile, Firefox might immediately make it your default profile. To test, scroll down to it and click the Launch profile in new browser button.

Did it work?

If so, you're done.

If not, you can close that window without affecting your regular Firefox profile and change back to the profile you started with before this post. Click the Set as Default Profile button below the other profile. And let us know what went wrong.

Wow, That worked. Thanks jscher2000.

Now I only have to resolve a very similar problem with migrating Thunderbird. Any suggestions?

Blessed be

Karma

Hi Karma, this forum has a separate board for Thunderbird, so probably a new thread would be best since I don't think the Thunderbird experts look at Firefox threads.

https://support.mozilla.org/questions/new/thunderbird

It is not recommended to copy a full profile folder from Windows to another OS like Linux as that can cause malfunctioning (some files contain absolute file paths).

You can copy specific files with Firefox closed to the current profile folder to recover personal data.

• bookmarks and history: places.sqlite
• favicons: favicons.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)