1. Totally freezes under what conditions? And it really freezes your PC, not just Thunderbird?

2. Please start *Windows'* safe mode with networking enabled - http://windows.microsoft.com/en-us/windows-10/change-startup-settings-in-windows-10#v1h=tab01 - win8 http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode - win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode Still In Windows safe mode, start thunderbird in safe mode - http://support.mozillamessaging.com/en-US/kb/safe-mode

Does problem go away?

In the title bar it says (Not Responding). Most of the time when that happens, I can't even close the window or close TB through Task Manager. If I'm patient (not my long suit) it will eventually respond. Something I forgot to mention is that this happens most often when it is downloading a new message, sending a message, etc., in other words, doing something else at the time. So, for example, if I'm typing a message, and it starts to retrieve new messages, I can't type another letter until it decides to respond. I use gmail, so I periodically clean out All Mail. Sometimes it's retrieving All Mail.

I also failed to mention I'm running W7 Home Premium on both the desktop and laptop PCs.  Desktop has 8G RAM, Laptop 6G. 

Thank you for your suggestion. Since it's nearing midnight where I am, I will wait until tomorrow to reboot and give safe mode a try and will post my results.

Hello again Wayne,

I booted in Safe Mode and have been using my computer (PC Laptop) as I normally would for the best part of an hour...including sending and receiving emails. TB is working without a hitch...as it does on my MAC.

So how do I figure out what is conflicting with it to cause the problem?

Thank you, once again, for your help!

What anti virus do you use on Windows? Do you also use it on the MAC?

Tend Micro on all.

I also went into MS Config and made sure there was nothing in startup that didn't have to be there.

TREND Micro...

please try windows safe mode with networking as Wayne suggested. This will disable trend while in safe mode. Lets see if Thunderbird does better without it.

I did do safe mode and TB did work fine. I posted earlier today:

"I booted in Safe Mode and have been using my computer (PC Laptop) as I normally would for the best part of an hour...including sending and receiving emails. TB is working without a hitch...as it does on my MAC."

Sorry to have missed it. So you have your answer. Trend is acting up and you will need to consult Trend Micro on how to stop it.

How do we know it's Trend? I use it on the PCs and Mac...no problems on the Mac.

I will check in with Trend though...see if they've any known conflicts with Thunderbird on PCs.

I'll post their response.

Thanks!

https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues documents that Trend Micro has been an issue in the past.

Please post your findings so we know if they have a better solution than http://esupport.trendmicro.com/en-us/home/pages/technical-support/1059964.aspx

Right now, running in regular Windows mode, I have Trend Micro shut off and TB is working fine. Certainly points to that as the culprit.

I'll pursue this with TM and will definitely post whatever I find out.

I'm very grateful for the input and being pointed in the right direction! I'll pass on anything that may help anyone else.

I'm back. I spent a "bit" of time with TrendMicro Support over a couple days. Ultimately, their suggestion was to add Thunderbird to the Exceptions List. I did that tonight and, so far, TB seems to be running OK. Over the next day or so I will see if it continues and post here with the results.

Adding to the exceptions list is easy. Here is the link I got from tech support. http://esupport.trendmicro.com/en-us/home/pages/technical-support/1059964.aspx

Basically you just open the main console, click on Settings (the Gear icon), then Exceptions Lists, Programs/folders, click add, then navigate to Thunderbird.exe and add it.

I hope this does the trick. I'll let you all know in a couple days.

PK (Angelmutt)

Sorry for my delay in updating my efforts to solve my problem. Unfortunately, I do not have good news. After many support "chats" and following their tiresome instructions (everything I had already done) there was no resolution and I ran out of patience.

Based on the fact that when I shut TrendMicro off TB works smoothly, and uninstalling and reinstalling TM does nothing, I guess I will call "Uncle" and get rid of TM in favor of another security program.

It still puzzles me - in a way, but not really - why TB works fine on my Mac Air running the exact same TM security. The "not really" part is because they are totally different operating systems/platforms. Clearly, something in Mac prevents what's happening with Windows/or, inversely, something in Windows is causing it to happen.

Thanks again for offers of help, and, again, my apology for not posting my activities sooner.

Totally up to you of course, but if TrendMicro is otherwise working fine, you needn't ditch it. By manually adding the exclusion, you are only doing what TrendMicro should itself be doing automatically, and you are not putting your computer at risk. See the previously mentioned wiki link.

Perhaps this is worth a look. https://support.mozilla.org/en-US/questions/1079237 This user has manager, he thinks at this point, to clear the slowness by adding not one exemption but five. It appears trends exception of for the folder only, not it's sub folders.

I've added some files and folders to the exceptions list (the Thunderbird program file and some profile folders and specific files, the latest being: C:\Users\Jonelle\AppData\Roaming\Thunderbird\Profiles\53oucn6f.default\ImapMail\imap.googlemail.com TBird does work better, but not seamlessly. Occasionally still does the "Not Responding" bit and other quirks. lf it gets too annoying I simply exit TM until I'm finished emailing and then turn it back on. I don't want to bother with safe mode; just make sure my browser is closed when I exit TM.