Thunderbird hangs my computer/machine periodically, rarely

It's not my task to convince you of anything, especially since you seem to prefer not answering questions directed to you (https://support.mozilla.org/en-US/questions/1571995#answer-1831681).

I'm here to gather information and give you the best advice based on my experience and the information I have. If that process isn't working then we are at an impasse.

Very sorry if I upset your sensibilities - not my intention.

Since I have tried everything you have suggested and reported the effects (ie in respect of global search) yet my issue is still there, I am sorry to report that I do not feel helped.

I repeat that when Global Search is active, TB hangs my system intermittently and for short durations. When I do not have Global search active, that issue - if not entirely absent - is significantly reduced. Unfortunately, Global search is an essential tool for me and it is easier to simply never run TB in the background rather than switch Global search on when needed.

I am trying - by doing everything you have asked - to help you to find the bug in the software which is manifesting itself in the issue I have reported. If you feel there is no such bug, then we are indeed at an impasse.

I don't know whether there is a bug. You still haven't answered the most recent question, which was not rhetorical, "you have configured [Defender] to exclude both the Thunderbird application program and the Thunderbird profile directory?". (The location of both of these are provided in Help > Troubleshooting information.

Apologies - I should have read further. 'Yes' to the app being on the Allowed list (this was asked about before) . However, I am not sure about the directory - I will get back.

I have checked the Defender folder exclusions and the Profile Directory is NOT excluded, The reason for this is that it would surely cause an unacceptable security risk. I would have thought that the one directory which should NEVER be on an exclusion list is an email storage folder. Or am I wrong about that?

Exclusion capabilities are part of AV products partly to get around problems like this.

And adding a profile exclusion does not leave you completely vulnerable - it is a misconception that all antivirus functions will be completely bypassed by setting certain exclusions.

Equally, decently designed AV solutions (and Defender should be with all the backing it has) are designed so that they do not intrude excessively in this situation.

In any case are you saying beyond doubt that an interaction between Defender and global search is creating this issue for sure - or is that just a tentative thought?

Perhaps everyone else instinctively creates a Defender exclusion when they install? Find that hard to believe and therefore what is different in my case that I need to?

Apologies - I should have read further. 'Yes' to the app being on the Allowed list (this was asked about before) . However, I am not sure about the directory - I will get back.

The install folder should be excluded, but it's not as important as excluding all of the profile folders, e.g. C:\Users\<username>\AppData\Roaming\Thunderbird\Profiles).

After you do that, go to TB menu > Settings > Privacy & Security > Security > Antivirus and enable 'Allow antivirus clients to quarantine individual incoming messages'.

Incoming emails will still be scanned: "Thunderbird first stores each incoming message in a temporary file in the system temp folder on your computer, allowing your antivirus software to only quarantine a single message."

https://support.mozilla.org/en-US/kb/security-panel-settings-in-thunderbird#w_antivirus-tab

> Equally, decently designed AV solutions (and Defender should be with all the backing it has) are designed so that they do not intrude excessively in this situation.

In a perfect world, yes, there would be no problems between AV and applications. But that is not the reality and facts are facts - some users have no interaction problems, but some users are in fact affected. To learn more and determine whether you are one of the users affected, it can only happen through your actions.

Please understand we are not in the habit of giving random advice. Further, several people generously helping users have decades of experience with Thunderbird plus technical computer professional backgrounds, myself included (click the link at my name).

" .....The install folder should be excluded, but it's not as important as excluding all of the profile folders, e.g. C:\Users\<username>\AppData\Roaming\Thunderbird\Profiles). ..."

Yes agreed - sorry that was the one I was referring to.

I will check and adjust the settings as you suggest and get back. Thanks for the steer.

I do not wish to demean the hard work in any way and I know how complex these things are. But then, from the user point of view, having to fiddle with system settings is a risky thing and is not one's first thought when just one app has issues.

We understand that aspect too - there can be stress related to making changes.

Thanks for that. I am away for a few days now, but I will try to do some experiments over the coming week or so with excluding the app, or the profiles folder or both, or neither with and without global search active to see if I can see a difference. It is not easy because the issue is very significant when it happens but may not manifest for quite a period of time which makes personal observation difficult.

It occurs to me that I could even have a go at writing a simple logging programme to record the system hangs...

If you mean logging which captures stacktraces WITH Thunderbird source symbols that would be great. On the other hand, stacks without symbols will not be helpful.