Ever since the upgrade of Thunderbird to 38.* I have had nothing but problems with Thunderbird stalling (spinning wheel waiting), a 'Mozilla Thunderbird (not responding)' in the header bar, the TB application window whiting out, and eventually the Box to Hell - a small box popping up asking if I want to - close the program, waited for it to resolve itself, or check the internet and then close. I now call it the Box to Hell (B2H - call it whatever you want but I am damned every time it pops up!) I have done everything suggested here to do and nothing fixes it. I have been using Thunderbird for years with all the same folders and add ons with NO problem. From day one of the 38 update everything changed. When will Mozilla realize that it is in the upgrade and find the problem!? Here is all that I have tried with nothing working... 1. I do not have AVG, only malware bytes and windows defender 2. It still happens in safe mode with no add-on activated. 3. I have stopped the saving feature which slowed the frequency of the stalling but did not eliminate the problem. 4. I have deleted hundreds of older emails thinking it was that but that did not do anything. 5. I changed some accounts from POP to iMAP thinking that was the issue but nothing changed. 6. I have made numerous attempts at fixes both on Mozilla Support and outside on the net. Nothing is working. In looking at all the people that have the same issues, I would have to say that the problem stems with the file handling. I have noticed this being the issue with others that have multi folders, and emails. The answer is not to reduce these volumes but to figure out why thunderbird handled them fine before and what has changed to make the program hang now? That has to be on your end, support. Keep us faithful followers and fix the issue.... Here are my particulars.... A. I have multiple folders and thousands of older emails for years and have manged them fine, as a matter of fact, Thunderbird has been awesome. Then like a good minion I trusted the moz and did my upgrade to 38. Never have had a problem before the upgrade. After the upgrade everything went to ****. B. The version 38 upgrade was a big change. When I would look in the folder that was labeled the Sent or inbox folder(where all emails from each account is gathered), all the listed emails would disappear when I moved my mouse over them! Disappearing emails! They were there in the specific email folders below it but not but in the head folder like it was just a day earlier and with out the upgrade. I figured that as an add on issue and waited for the fix that happened not so long ago. Again, that may have been an add-on folder issue . C. The upgrade to 38 had other issues but if going from no issues to craziness was not bad enough, the problem seemed to get worse with each 'update or bug fix that followed. Don't hold me to it but I think it was in 38.1.2 or 8 (I think that was it. I was not paying attention but had I known I would be having to recount this, I would have!) That is when the hanging got interminably long. When the program closed at least I had a draft saved, then I read on line that the saving of open messages was the problem so I turned the auto save off. It did change the frequency of the hanging (white screen pausing) and stalling (where the B2H pops up) but it was still there and still is! D. I had hoped that with 38.2 there would be improvements. Nothing changed. I was sure that 38.3 would make that change/fix but nooooo. So I am writing all this so you have what I know as a faithful user since 2007. E. Here is what you need to complete the picture. I am on a PC running 8.1. on an Intel i7-4770, with 32 gb ram, now you tell me when you will issue the update to fix the problem! Again, Mozilla, I would suggest that you begin looking at how TB 38 handles multi emails, folders and archives. Not all of us only have one email account. Most of us have been really happy with TB prior to 38. If you can't find the issue, can you show us how to go back to a version prior to 38? Thanks for listening and hope all this helps!! @v@