I seem to have a collection of address books from previous versions of Thunderbird and their file extensions have changed.

What is the current address book extension type and what was the previous extension type?

Hello

the current extension is .sqlite. The preceding format was .mab (a format specific to Thunderbird), in my setup the switch occurred mid 2021 (I have .mab.bak files from this date). The sqlite format seems to have evolved rapidly during last year since I have old files .v2.sqlite and .v3.sqlite (the sqlite format is standard but the database format has probably evolved). Manual conversion of mab files to sqlite seems to be possible (search the internet for a site called recoverytools with a com tld). I have never used their tool, mind, so good luck with it.

Various formats, including .sqlite and .mab, can be imported in Address Book (see picture).

Reporter,

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Thanks