https://support.mozilla.org/en-US/questions/1453832 reports the same issue

I wonder if anyone is working on this? Thousands of duplicate messages are really slowing down Thunderbird!

How is version 128?

I just updated to V 128. As of now, 12:04am on Aug 2, all inbox messages from 4:05am on June 5 and older are duplicated. This includes messages that have been read, many of which I had already deleted their duplicates. They are duplicated again.

So, I tried the "Rebuild (inbox) Folder" in Edit Folder Properties. Now, the message list says No Messages Found, while the inbox count says 91,000 messages. It should say over 100,000.

I tried the rebuild again, I tried renaming the 'global-messages-db.sqlite' file (not deleting it), and still, no inbox messages.

Each time I try to open Thunderbird, I can se that it tries to rebuild the folder. I get an error message saying that the folder in use by another process. Eventually the program will crash entirely.

What other steps can I take to recover my email?

Thank you

A bit of progress... After rebooting the PC, I now have an Inbox listing. However, any message I open that came in prior to now appears to be blank. To/From/Subject and body is empty.

I did a new install of 128 and imported my profiles. Everything worked fine but this morning (a day later) all my emails are replicated. Even new emails are replicated. It is very annoying :(

I would really like to be able to read the inbox messages that came in before rebuilding the folder. And yes, prevent the duplicate listings.

And now, after compacting the inbox, some recent messages are blank /not readable, that were readable before compacting.

Very frustrating!

My inbox shows 358,566 messages. Half of those are duplicates!