What is your anti-virus software?

Was not expecting a 'question' to my question but; I had Norton Anti-virus but noticed (some) unwanted 'company' and (they) were implanting themselves (too) deeply into my files, etc., so went to Kaspersky (where the problems started) and now I have McAfee. Not sure if everyone is having more problems with spam since they were given more leeway a while back or 'I' am just lucky (20-30 (+) a day). Obviously my E-Mail address got into the wrong hands. Hard to 'opt out' of 'everything' annoying. I haven't tried a (full) 'system restore' this time. Hate to go there but may need to. Microsoft (decided) I need Windows 8.1 again so when I walked away from their 'up-date inquiry' then came back they were already re-installing it (claiming I 'need it' to avoid problems). Like I had 'on it' (?). Anyway, T-Bird still brain-farts all over the place.

Your problem is McAfee. https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#McAfee

I will try this one more time as the last time I replied T-Bird crashed right in the middle of it (highlighting the problem). As said previously; my problems started with Norton as my anti-virus security system, then Kaspersky (where the spam count jumped) and now McAfee. So, I can not qualify the advise to blame the (last) antivirus hooked-up. Logic does not assume this to be a fix. I was just in hopes that this (being a basic problem) would look familiar to 'someone' and have a 'go-to' response to nail it in it's tracks. I am losing patience with this on-going crap so if no fix (soon) will no doubt cut Mozilla loose and go elsewhere though I hate to do it since I have been mostly loyal to them for years but enough is enough. Firefox drops a stitch now and then, too, but not every frickin' 10 minutes so looks like a 'Mozilla' thing (in general). Thanks anyway.

Any discussion about anti-virus products you used before is hypothetical. It is entirely up to you to follow the instructions posted above wrt McAfee. If you choose not to, that's fine. But then I'm done with this thread.

https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#McAfee cites *many*examples where McAfee causes issues. I've added more than a dozen in the last week.

The advice does not necessarily involve turning *off* McAfee. It first suggests disabling a feature of McAfee that is frankly not needed and known to cause issues. And also suggests how to ensure that McAfee is not scanning Thunderbird directories, which it is NOT supposed to do, and has been broken several times over the years.

McAfee is not the only one that fails in this area, but it seems to be the most common.

I did try to follow advise (Wayne Mery) but what (I) found when trying to go after this prob. was not exactly as described. Maybe different on my system (?) or messed up some where. I did not customize my scan so went by the scheduled scans and had a hard time finding (specifically) the files mentioned; like McAfee Anti-Spam Thunderbird Extension. Looked both in the T-Bird files and McAfee for (that) specifically and ended up (probably ill advisedly) guessing on what to exclude from scans and not sure what was meant by 'click' Schedule Your Scan (and 'then') 'click' Excluded Files and Folders as they were not on the same selection page and not able to work in unison. Do I need to put the specific files in a folder first for access to 'exclude' them? I (obviously) can not exclude (all) of T-Bird scanning as it is needed to run (this and that), etc. and would be 'warned', etc.

I (did) put two on the exclude list; the 'Thunderbird.exe' file and the 'Profiles [1]' (history file) but this made no difference as got 28 on spam file next day. They are however (just) in the spam file and (not) showing up in my 'in-box' or 'all mail' like (some) did previously but still I did not get enough to be concerned about (before) update to W 8.1 some months ago, etc. I apologize I as I am (not) that qualified to hunt down and recognize what those do who spend (way) more time on their PCs then I do. You (may) have to dumb it down a notch to be successful on deleting the McAfee Anti-Spam Thunderbird Extension. In 'tools' in T-Bird it shows no such 'Add -on' to snag and deal with. Had already dumped the Add-ons previously (and restart) and in Safe Mode hoping for the change (I did not get). In 'Disable scanning of T-Bird files' (specifically) did not see in 'Real Time 'Scanning' in McAfee (?)  and where is this 'systray icon' to 'right click'? (And) 'Sith' Windows in safe mode? Sorry, simply can not find some of these. I contacted McAfee and they replied they set up a work order (over a week ago) and have not heard back. Even when sending prob. 'again' so, guess they are not interested.

'CHRIST'............ 'You' asked 'me' what anti-virus product I was using. I replied. You say my problem (is) 'McAfee' and then tell me "any discussion I used about anti-virus products is hypothetical" in that I experienced the same problem with (varied) anti-virus products. Not grasping your 'logic' there.

Is hard to follow your long sentence, long paragraph style of writing. But I'll pull out this one item

> Do I need to put the specific files in a folder first for access to 'exclude' them? I (obviously) can not exclude (all) of T-Bird scanning as it is needed to run (this and that), etc. and would be 'warned', etc.

No. You exclude ALL of thunderbird, the entire profile with all it's subdirectories. Exactly as described at https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#McAfee