I've copied my Thunderbird profile (a directory called like f4gokpr4.default) from one Windows 10 machine to another Windows 10 machine. Account names are the same, all absolute paths I know about are the same as well.

However, now a lot of folders in my POP account are missing in the interface. Top-level folders are there, but they contain no letters and no subfolders.

The thing in common is these directories have Cyrillic/non-Latin names like Работа and contain special characters like Путешествия/Отдых (that's a single folder, not a subfolder). In the profile folder they correspond to files/directories Работа/Работа.msf/Работа.sbd, and something like Путешествияf88e4aec/Путешествияf88e4aec.msf/Путешествияf88e4aec.sbd. Cyrillic characters are stored as-is, and everything after a special character is truncated.

However, on the new system Thunderbird thinks that these folders should be stored in a newly created directories like 44d8f9af/44d8f9af.msf/44d8f9af.sbd. These directories are created in the profile, are empty, and no files/directories are moved from the previous location.

All-Latin directories work fine.

How do I make Thunderbird use the old directories instead of trying to give them new names?

1 Answer 1


I've found a kludgy solution on Mozilla Support: turns out my profile was created on a machine which has used Russian (Russia) as the system locale (Current language for non-Unicode programs), but the new machine has English (United States) instead.

Solution: switch the new machine to use Russian (Russia) locale as well, restore from backup one more time.

As far as I understand, this affects the default non-Unicode encoding, and Cyrillic characters can be encoded using Russian (Russia), but not English (United States). It seems that Thunderbird either uses non-Unicode API to query the filesystem, or uses this system setting to determine how to store directories on the disk.

  • +1. Very interesting. I wonder, after the backup, can you now switch locale to english? or are you now stuck on russian? And also, if you can switch to english, would a backup then allow being imported on a system that was never russian?
    – LPChip
    Oct 14, 2022 at 13:39
  • @LPChip I'm stuck with the Russian locale. If I switch to English, folders disappear. If I then switch back to Russian, folders reappear, but their duplicates with ASCII-only directory names remain, so I end up with 2-3 copies of each folder in Thunderbird.
    – yeputons
    Oct 14, 2022 at 15:16
  • Odd. Too bad that happens. You can try unzipping the export and see if you can edit anything and import it back as english.
    – LPChip
    Oct 14, 2022 at 15:28

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