From my own experience, doing a backup is often not successful if Thunderbird is running at the same time. Are the local folders still 1.47 GB, or was that the size prior to the backup?

Thanks David

I copied my entire Documents folder (where the TB Local Folders are) to an external SSD before the Windows reinstall. I also have many copies on my weekly Acronis full PC backup going back to Feb this year. They are all the same size as the one on the SSD. I'd be gutted if I'd lost them all going back to 1998

If the size is still 1.47GB, you might try exiting TB and copying the folder into the Mail\Local Folders folder of the profile, and restart TB to see if it can read it.

Hi David - there was some server problem yesterday and I couldn't reply. I tried your suggestion, but it didn't work, so I stated to get a bit anxious I'd lot the lot. I've been trying all sorts of thing over the day.

Anyways - long story short I recalled a previous post that you helped me with when I first got this PC and having reviewed that it pointed me in the right direction. Just now I restored the entire Thunderbird folder from the Acronis backup I done on 4th June and as if by magic everything is there - phew It's mainly sentimental stuff going back to 1998, so very pleased not to have lost it.

Once again, thanks for putting me on the right train of thought!

You're most welcome. :)