Did this happen immediately after an update to Thunderbird? If so, have you tried restarting Thunderbird?

It just seemed to happen. I don't think an update was involved.

I finally sorted it out after several hours.

I deleted all of the thunderbird files in program files. Reinstalled an old version (91.11.0), defined a new profile and then upgraded to latest version (Thunderbird Setup 102.3.3). Not sure installing the old version makes a difference.

Not sure how many of the steps were essential. Just installing a new version of thunderbird makes no difference. It looks like defining and activating a new profile seems to be key. I can only assume that there is some setting in the registry that is causing this issue. Note that I initially didn't create a new profile as I had an existing one on a seperate drive that had all my existing emails.

I reiterate, I could receive and send emails using the corrupted version of Thunderbird. This is a display issue. There was nothing that worked to sort out the display using menu options

Thanks for the update, and kudos for resolving the issue! Glad it worked out, but I am sorry that you had this problem to begin with. Thanks for using Thunderbird.

In your old profile you could try the following

Access profile name folder - Help > Troubleshooting info > click the button next to Profile Folder Exit Thunderbird and rename these files:

• folderCache.json
• folderTree.json
• session.json
• xulstore.json
• virtualFolders.dat
• Click on 'Mail' folder and delete 'smart mailboxes' folder