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Thunderbird 38 hanging, freezing, and not responding issues. 17 pop accounts. (Win 8.1, MalwareBytes, and Windows Defender)

  • 43 uphendule
  • 12 zinale nkinga
  • Igcine ukuphendulwa ngu niteowlsawake

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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@

Okulungisiwe ngu Wayne Mery

Isisombululo esikhethiwe

Here is a follow up on the slow hangs and freezes... My MO... I abuse my TB and it was fine until it wasn't. if you tried to use imap but decided you rather go pop than imap like me but are now plagued with issues of hangs and white screens, here is what I did....

Besides coming here to complain about my problem, Matt took me through a lot of stuff I did not know existed and it helped me understand what I could and could not do... so thank you!

Bottom line.... (my advice)

  • Clean up after your bird (TB)!
  • Organize your emails, dump the trash, keep the volume of emails to a small roar (under 1800 per account)
  • If you tried imap and when back, delete the account (after backing up your emails) and reestablish it clean as pop.
  • Try getting rid of the add-ons you really don't need.
  • If you are still having problems, turn off the indexing by windows.
  • if still having problems, turn off the indexing by Mozilla.
  • If you are still having problems, strip that pup and go naked! Safely that is.... Go into safe mode. >Help> Restart with Add-ins disabled.
  • Stay there for a while until you appreciate all TB offers you!

Now restart again and see if it is better. It worked for me. Maybe the updates had a fix that helped but this is all easy to try and good practice. Hope it helps you too.

Good luck!

Funda le mpendulo ngokuhambisana nalesi sihloko 👍 0

All Replies (20)

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I wish you had continued in your previous posting at

It's great that you have tried all those things. And I can understand how you reach your conclusion about some file IO changing in Thunderbird.

But that is not the case. Plus, with 10-15 million users already on version 38.3.0 we have no open version 38 performance regressions in our bug database -

Please visit

Skip the items you have already done. Let us know the results of going through the list


> 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!

This is a different issue. It will be helpful if we investigate only one issue per support topic. But I can tell you this was probably because of the video hardware acceleration that was enabled in version 38.0.1 and 38.1.0. We turned it off by default in verison 38.2.0

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It will be a bit before I can carve out some time to follow through on this list of stuff. So don't close this thread because of no response. I promise to follow through as soon as I can.... Maybe while thunderbird is locked up and I am waiting for it to recover from itself!

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Okay, I have started going through the list of suggestions within that link you gave me. I think the third one was related to gmail and the effect of multiple folders with imap accounts. So I looked through my 19 email accounts and noticed that I had created a 2 imap accounts from non google servers. Thinking that if google has issues maybe smaller servers did too. (also it would be easier to deal with 2 accounts than the 9 other gmail accounts first.) So I removed 1 of the 2 accounts and reestablished it as a pop account. The emails downloaded and all remained working. When I restarted TB, the several minute startup where I could not even click on the TB screen without it going to the white screen of death was better. Now the startup is one minute and while I get the hang time, the white screen seems does not happen. I only get the "(not responding)" in the header. The account I changed was fairly new so I was not risking much data. I will need to go through the other account and be sure I save the emails before I do anything. It may be a while but I am offering this for those with this problem because there is an improvement. Not fixed but better.

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Yes I am slow at replying to my own questions but no one seems to have the same issue. So I am essentially talking to myself here.

I did resolve one issue.... My slow start up has been improved by unchecking each account's setting that retrieves all emails at start up. I now have a few second wait and then I click get all and it seems to not take as much time.

Hope that helps someone.

I am now getting TB creating subfolders out of my emails within the Local Folders. What causes this? Though I have painstakingly tried to delete them these folders, they come back every time I restart TB. Any ideas what is happening with that??


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niteowlsawake said

I am now getting TB creating subfolders out of my emails within the Local Folders. What causes this? Though I have painstakingly tried to delete them these folders, they come back every time I restart TB. Any ideas what is happening with that?? thanks

sorry, no idea

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p.s. how many pop accounts? how many imap accounts?

And, is the "not responding" issue characterized by a dailog popping up and saying (exact wording) "Unresponsive Script"?

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Wayne Mery said

p.s. how many pop accounts? how many imap accounts? And, is the "not responding" issue characterized by a dailog popping up and saying (exact wording) "Unresponsive Script"?

There are 17 accounts. At one time there were 3 that were imap. Now I have converted them all to pop. That helped but it still does it when I catch it trying to do something and I click on the window which locks it up. The way that the notice comes is only with the header showing "(not responding)" next to the 'Mozilla Thunderbird' and if I click anywhere in the window the whole thing goes white and there is a lag of approximate 2-3 minutes where nothing can be done.

No I have not continued on as I am on a huge project that leaves little time to trouble shoot. The indexer fix sounds interesting and a good possibility over the antivirus. I have turned off the indexing. Let's see how that goes. Thanks for checking in on me!

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Have you tried creating an exception in Windows defender for the Thunderbird process?

For all the issues, windows defender makes Thunderbird run slowly for many people. I am not sure what the triggers are.

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Okay of the procedures asked about above ( 3,4,6,7 in ) I have have tried turning off the indexer. That did not work.

I have 32 gigs of ram mem if that helps any.

I have added Thunderbird to the exceptions in WinDef as suggested above and in the wiki article. That did not work.

Last weekend I upgraded TB as per the pop up and if anything, the hanging is longer now and more frequent as in happening with every email where as it was generally with more complicated emails (simple text to one or two people would not cause hanging but 3 or more recipients and or an attachment or long dialog would kick the (Not Responding) hang).

My recent attempts listed here were tried after the upgrade to 38.6.0. and now every email there is a hanging.

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So I have stopped TB from retrieving messages when I start it up. If I click anything the window goes white and hangs. According to #7, it says that there is a search that it does that can be turned off. I noticed that there is the word 'searching...' in the lower left corner at start up that is present when it hangs. So I turned it off and still I get the white screen and hanging.

I have turned off the indexing and still it is happening. I am now more aware that there is some function is it executing on its own that is hanging the system. I turned off the auto save, the email retrieval, the antivirus checking, what auto function is left?

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searching? that might be looking up the server names in DNS.

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I think "Searching..." is what's shown while it's opening a message looking for images [1] or loading the folder index from disk - and in some cases (re)building it if necessary. This symptom may also be related to the screen going white.

What are your settings for these accounts for a) getting new mail at startup b) getting mail every N minutes?

Then, we may need more information once you get more time to go through


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I have turned off the checking/retrieving of emails at start up because it would take 3 minutes to start responding. The retrieval at start up the start of my issues. that is also why I removed all imap retrievals and am solely pop now across the accounts. No more hang at startup unless I try and click anywhere in the TB window right away. I have to give it a bit for that 'searching' to stop. I was able to stop the searching now so that is not in the lower left corner but it still acts like it is occupied doing something so I wait before starting to email. I have retrieval every 15 minutes after the initial start up and manual retrieval and I cannot say that it hangs each time but if I try and do anything while it is retraining it I get the hang (NR) and white screen. I think the indexing issue is one of the problems that I will tackle next. I will look up how to rebuild the index.

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On the toolbar > Help > Troubleshooting Information

Click the show profile button in Troubleshooting Information Close Thunderbird In the file window that opened, delete the file global- messages-db.sqlite Restart Thunderbird.

The search will be rubbish until the file fully regenerates, which could take a whole day if you have 10 or 20Gb of mail. You can monitor the status of that using the Activity Manager.

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Okay, I have deleted the 1.5 gig file and it now is 210 mb and growing. I had the indexing turned off at first from an effort to stop the hanging. When the file was not increasing in size and I was still getting the hanging, I turned it back on and the file is now populated.

When I used Outlook Express, I could delete the folder called File.dbx and it would only delete the file tree (how my folders were organized) and not do anything to the emails in the files themselves. I am seeing a generating of folders created from emails that will not disappear no matter how many times I delete them. So they must be generated in the download or stored in a file hierarchy that I do not know where to locate. My question now is ... does TB have such a file that is solely records how the files are organized that I can delete without loosing anything and that it will rebuild automatically, like the index file I deleted as per instructions... global-messages-db.sqlite? I think that I need to resolve the file issues next and then return to the indexer and delete it again to see if there was some corruption in the folders that kicks this program into stalling.

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Thundebird does not use binary files to build it's folder tree. it is based on the existence or not of files and folders either in the imap mail or mail folders.

There is a foldertree.json file that can be deleted to remove the cached version of the folder tree. Only delete anything with Thunderbird closed.

But I simply do not understand " I am seeing a generating of folders created from emails that will not disappear no matter how many times I delete them. So they must be generated in the download or stored in a file hierarchy that I do not know where to locate. " what exactly are you seeing. Perhaps a screen capture would help to visualize what your talking about.

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Here is a screen shot of my LOCAL FOLDERS. It has been redacted but you should be able to see what is happening. On the left that one of the accounts on the left is one of the email accounts that this 'email into folders' events have occurred. I cannot tell you when or how just that they popped up at some point when I was trying to organize things. Here is what I know... It has occurred on 5 of my 17 accounts. I cannot link it to anything like imap as some were imap'd at one time and some not. I cannot relate it to gmail as some of the accounts are and some from my website host. The account specific info is highlighted in pink. I have super imposed the Account info as it is the Archived folder where this occurred. All the emails in this one account (there are 5 accounts total this has occurred in) that each email was converted to a folder. If I click on the folder you can see that there is no info that shows up in the main windows. I cannot open them inside or outside of TB. All my accounts have designated archived folders not system assigned so with only 5 of them doing this I cannot blame it on that. I have deleted them numerous times but they all reappear even without restart so they are retrieving this from somewhere. The last oddity of these is that this occurred to existing emails. I have dates on these folders as emails that I received back in 2013.

I was hoping that a folder tree file existed that would be able to be deleted and break the chain to these phantom files. This folder thing started within the last 6 months when I started actively seeking resolve this system hanging issue though because these are archived in the Local Folders, I did not discover them at any distinctive moment in my attempts to problem solve and thus am unable to link them to what it was that I did to generate them.

So what do you think? Have you seen this before?

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Just to add to the above... I closed TB and located the folder holding these folders. Each folder has a second of the same name with .mozmsgs added to it AND there is another file that is generated as well that has an extension of .msf for each of the folders!!

Any better idea now?

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I can see exactly what is going on. Just how you got there I have no idea. but your have EML files in your folders. Thunderbird does not use them at all, and as you see their presence, or the presence of any files really, is causing trouble.

Did you try and move mail from another machine, or import from a backup or something?

I know what needs to be done, but how is really going to depend on you.

Are you familiar with a command prompt and comfortable using it? Is your account on the machine an administrator account?

What is the full path to you profile folder. Most likely 8 random characters and the word default. I as because I would like to be exact in my instructions. It is really only relevant to you, except command line stuff in not very forgiving of errors.

What has to happen is all the EML files have to be moved out of your profile. We can figure them out later. All the MSF files have to be deleted. all the mozmsg folders have to be deleted as well as the files they contain.

As an aside, do you use windows search to locate emails? If not we should tun of the windows search integration and delete the files generated to support it. Your profile will shrink to like 50 of what is was as all mail is duplicated for that integration.

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