Try to start *Windows* in safe mode with networking enabled.

- Win8 http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode

Still in Windows safe mode, start Thunderbird in safe mode.

- https://support.mozilla.org/en-US/kb/safe-mode

Does the problem go away?

I have to wonder if having no anti-virus software other than Windows Defender means a virus is causing the problems. Surely that is not sufficient protection?

Anti-virus was proposed as a possible cause of my TB problems.

I hope to come back to TB in a month or so. In the meantime I'll have to stick with Verizon Webmail. Oh well.

... come back to TB in a month or so.

And what do you expect to happen then?

HISTORY I have lost a lot of time, running full system scans with defender updating Windows, TB, etc In TB creating new profiles, creating empty folders under local files, saving all mailboxes in a separate folder called "mail prior to June 1, 2014". Moving only abook.mab and history.mab, and mail box files (no extension) with things in I need to work within the short term. NOT pref.js or Training dat. (I did not move those in case they were what carried the corruption. some of the contents of prefs.js referred to profiles and printers I have not had for a dozen years. It was close to 2000 lines. Training data might have been filtering things at least that old. If I recall correctly Thunderbird had another name that I may or may not have simply updated. Was it "Netscape" or was that the old browser? )

SHORT TERM In the meanwhile I have been doing all my mail on Verizon. Moving only a few files to TB. I do not know if the freezing has been cured. But I still get the messages with blank subject, blank sender, and 12/31/69 dates.

LONG TERM when I catch up for the time I spent

I'll try a couple of other free AV programs to see if they find anything.

I'll do a new search WRT 12/31/69 dates.

I'll set up a completely new user ID on my PC.

Then I'll make a new TB profile with only my ISP information.

I'll try this process with and without Windows in safe mode and with and without TB in safe mode. I'll see if I get freezes, 12/30, 1969 messages, etc.

--I'll move a few unimportant messages into my Verizon inbox. 

-- tell TB to "get mail". -- create a couple of folders and try to move some messages into them. -- try to delete some messages. -- compose some messages -- -- save them to Drafts -- -- send them to a user called "test" on my personal domain.

See what happens.

I have this exact problem on a brand new DELL laptop. I'm using McAfee and running WIN 7.

Interestingly, on a 3 year old DELL desktop I'm also running WIN 7 and TB and have never seen this problem.

Would an upinstall/reinstallhelp?

I did try that. I removed TB from my computer and re-installed it.

But I should prbably do it again when I return to using TB for receiving mail. For now I am only using it when I want to compose new email and need the address books.

rcaastro, re-installing the application seldom solves a problem, as most of the times the problem is in the profile.

Since you're running McAfee you problem is different. Please raise a new thread for your issue. You may also search this forum, there are plenty of threads wrt McAfee.

I found this link <https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#McAfee> and followed the suggestion re disabling the email scan function by McAfee.

Ta Da! It seems to be working, by which I mean that when I delete emails in TB, I don't get any screen freezes or 'not responding' messages. If this remains stable for the next few days I'll consider the problem solved and probably uninstall McAfee.

You hit the nail on the head.

I found disabling the McAfee scan of attachments worked and I no longer had freezes and lengthy delays. I finally managed to contact McAfee (which is provided free as part of my service provider package) and was told I should not disable the attachment scanning. They told me to unistall my anti-virus and then re-install it. As expected, the problem remained.

I am investigating the use of a different anti-virus programme. In the meantime I have stopped using Thunderbird - which I much prefer, and am using Postbox. It is amazingly free of any problems. But I still prefer Thunderbird. Considering Postbox is a copy of Thunderbird, why can't Thunderbird copy whatever it is with Postbox that is not having issues with anti-virus software? Or is it that perhaps McAfee doesn't even recognize Postbox and therefore doesn't scan the attachments sent through it?

I've seen this issue on every Win 8 installation as well. It seems to be caused by contention; Thunderbird and Windows Defender are doing a lot of disk IO on the same files.

The solution is simple: exclude the Thunderbird profile directory from being scanned by Defender.

Open Windows Defender (Start -> flick up or use down button with mouse -> Look for "Windows Defender" under the "Windows system" header).

Go to Settings, "Excluded files and locations" and use the Browse button.

Find c:\users\<your username>\AppData\Roaming\Thunderbird\Profiles

Select this directory, then press the "Add" button.

If the directory is shown in the bottom dialog, press "Save changes".

All done, Thunderbird should be ready to go, without performance issues.

@dev team: this might be something you want to automate!

I tried putting this directory in windows defender. I then shut down and restarted my PC.

I then sent myself some email from another account. I still get email with a blank subject and 12/31/1969 date.

(1) Wouldn't putting this directory in Defender mean the email was not scanned for malware?

(2) Is there any way to test mailboxes to see if they are the source of the corruption?

I tried putting this directory in windows defender.

What exactly does this mean?

a few entries earlier in this thread roelbouwman suggested putting the name of the directory that contains the TB profile in the Defender list of folders to exclude from scanning.

I tried that. It did not work.

@ArtKendall: are you sure you have added the right profile dir? I have four Win8 devices and have had to do this on all four of them. It solved the issue each and every time.

I copied and pasted it from the server settings. I also used windows explorer to navigate to the folder to check the name. It matches your suggestion except of course the actual user name.

I once again deleted all files in the profile under pop.verizon.net except msfFilterRules.dat. I then restarted TB and created 3 folders under INBOX. When I clicked <Get mail> the 8 messages I had on webmail were downloaded but an additional message with blank subject was created.

I copied and pasted it from the server settings.

That doesn't sound right.

For more information on the location of the profile folder see http://kb.mozillazine.org/Profile_folder_-_Thunderbird

I once again deleted all files in the profile under pop.verizon.net

Why would you want to do that?

Please let me clarify. wrt the string specifying folder to exclude in Defender I checked it a few ways

--- I opened TB found the profile name it was looking for. I copied and pasted that into Defender and deleted the actual profile name. --- I then browsed in Defender to the profile folder and saw that it was the same. --- I then used windows explorer to get to the profile folder. All strings were the same. --- They also matched the location you had in your message except for the user name.

Wrt deleting everything in the profile under pop.verizon.net They were all empty, and because one cause of the problem could be a corrupt inbox, a newly created one should not be corrupt.

Your original problem was about Thunderbird freezing when deleting messages. Do you still see that now?