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Steps to reproduce:

In a Thunderbird update (?) the contents of several address books were deleted. How can I recover them. Not sure what steps to take.

Address books were migrated to the sqlite format.
If there were problems, in the profile find the old ones (which were renamed .bak, like abook.msf.bak), and in an older Thunderbird export them, then import in 78.

Please help us by telling us the exact names of the address books that were not migrated, and also be sure to preserve the files in case the contents are a useful testcase. You will find them in your profile https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data

All of this is too geeky for me! Out of 15 address books, I lost the contents of 7. The names are still listed, but contents are missing. These are the names of the missing: Birding, Birding Texas, Computing, FAMILY, Harte Trail, SAM, Vasa Lund. Finding these files is problematic - at one point I did find them, but no ".bak" extensions as indicated.

Lars, thank you for posting additional information.

(In reply to Lars from comment #3)

at one point I did find them, but no ".bak" extensions as indicated.

This finding is consistent with certain address books not being migrated to the new format, or not fully being converted.

All of this is too geeky for me! Out of 15 address books, I lost the contents of 7. The names are still listed, but contents are missing. These are the names of the missing: Birding, Birding Texas, Computing, FAMILY, Harte Trail, SAM, Vasa Lund.

So you have 7 address books whose names appear in the address books window, but those address books have no contacts listed in them?
Can you post a screen shot of the directory showing the file sizes all .mab and .sqlite files?

(FWIW I tried to find another report if this, but failed. https://mzl.la/3d2vxg2 )

(In reply to Wayne Mery (:wsmwk) from comment #4)

Lars, thank you for posting additional information.

(In reply to Lars from comment #3)

at one point I did find them, but no ".bak" extensions as indicated.

This finding is consistent with certain address books not being migrated to the new format, or not fully being converted.

All of this is too geeky for me! Out of 15 address books, I lost the contents of 7. The names are still listed, but contents are missing. These are the names of the missing: Birding, Birding Texas, Computing, FAMILY, Harte Trail, SAM, Vasa Lund.

So you have 7 address books whose names appear in the address books window, but those address books have no contacts listed in them?
Can you post a screen shot of the directory showing the file sizes all .mab and .sqlite files?

These are in the same directory - found by going to Help > Troubleshooting > Profile Folder

Lars,

(In reply to Wayne Mery (:wsmwk) from comment #5)

These are in the same directory - found by going to Help > Troubleshooting > Profile Folder

Another route is Help > Troubleshooting > about:profiles > click on "open folder" for the root directory listed

Resolved per whiteboard