That screenshot was after you told me: "Richard, if you still have the blank tabs on startup, please check the error console (ctrl+shift+J)"

So I see my sending you a screenshot after you said that made it look like I still have the blank tabs.

But actually when I made and sent the screenshot was about 3 hours after I wrote this to Wisewiz: "Now all those emails in tabs I had been saving are not even blank tabs anymore. The tabs are gone." So the screenshot was after I had no tabs at all, not even blank ones.

It won’t surprise you to hear that your use of tabs is possibly unique in this universe, and that the developers probably had no idea that the program should accommodate such a storage solution. I’m surprised that TB supported the practice at all, up to a limit. Please consider creating a Local Folder for the.purpose you’ve been using tabs for. That will be infinitely safer than what you’ve been doing. Good luck, and thanks for sharing your experience.

I also use tabs to keep important emails open that I have to action. This response is very....I won't say it. Anyway, the actions suggested by most of the helpful replies are still way too technical. Can someone simply correct this damn glitch?

I have this problem as well. 115.6.0 (64-bit) "delete session.json from the profile folder" is temp fix but blank tabs return at random.

I don't believe that the blank tabs return at random. It's your open tabs that get detached from the underlying emails by auto-updates. This was also discussed in https://support.mozilla.org/en-US/questions/1425364 but nobody came up with a working solution. Unfortunately, it looks like 115 updates tend to corrupt session.json with no way to recover the tabs once the email IDs are gone. It happened to me again with the 115.9.0 auto-update. Nobody from the developers has responded or taken steps to mitigate this well documented auto-update bug. So the situation remains "oops, I did it again". Catastrophic for people using tabs as workspace.

Nobody from the developers has responded or taken steps to mitigate this well documented auto-update bug.

I do not know where you think you are posting,  but this is a peer support forum.  Not somewhere developers even appear, let alone offer support.

If you have feedback, there is a forum for that. It is linked from the help menu in Thunderbird to https://connect.mozilla.org

If you wish to report a bug, there is a bug tracker for that. https://bugzilla.mozilla.org/home

What I can guarantee to you is you will not get any response from developers in this forum, unless they are seeking additional information on something they are working on. As for this Bug that is well documented in your mind. Has it even been reported?

I searched for bug with a session.json mentioned in a comment (including Firefox) https://bugzilla.mozilla.org/buglist.cgi?list_id=16977254&resolution=---&query_format=advanced&longdesc_type=allwordssubstr&longdesc=session.json&classification=Client%20Software&classification=Developer%20Infrastructure&classification=Components&classification=Server%20Software&classification=Other of the 24 reported bug that were still open I saw one report from 2 years ago on Linux that might be similar. https://bugzilla.mozilla.org/show_bug.cgi?id=1758872

As that bug has no resolution, or even reliable steps to reproduce, your assertion that it is well documented, with the implication that the issue was understood or even accepted as a bug, is rather tenuous.

There is a misunderstanding that session.json is at fault, perhaps because I suggested deleting or avoiding using it. Those requests were only for testing.

We have in fact fixed some tab issues since the supernova UI code was introduced in Jan 2023, so the assumption that nothing has been fixed or developers not informed is incorrect. But Matt's bug query (simplified here) https://mzl.la/4au1OcD does not list any fixed bugs, because the fixed bugs don't mention session.json.

Bug query which focuses on tabs: https://mzl.la/49qBmPR - so this is well documented in bugzilla, with unfixed reports.