User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

http://peter.drealm.info/img/ThunderbirdAbout%202019-04-04%20192917.png

Background info.
My profile is on a network drive.

Windows says it's 632Mb of files but 20.2GB "on disk":
http://peter.drealm.info/img/ThunderbirdProfileSize%202019-04-04%20191616.png
... which looks rather odd.

An awful lot of this appears to be the cache2\entries folder:
http://peter.drealm.info/img/ThunderbirdCacheEntries%202019-04-04%20192104.png

There seem to be two situations - one immediate fail, one that happens "after some time":

Situation 1 - always causes fail:
flag a message as spam
Here's what Thunderbird thinks of my Junk folder:
http://peter.drealm.info/img/ThunderbirdJunk%202019-04-04%20192534.png

Situation 2 - running eventually causes hang:
run Thunderbird for a period of time (hard to say how long)

Actual results:

Situation 1 - always causes fail:
Thunderbird hangs (unresponsive until eventually either I kill the process or Thunderbird decides to send a bug report)

Situation 2 - running eventually causes hang:
Either Thunderbird hangs whilst I'm using it or I just find I've got the bug report pop-up after it's died. In either case, it's hard to say whether it's a constant period of time as I'll not have noted the start time in the first case or know the actual fail time in the second case (rather than the time I discover the popup).

Expected results:

Situation 1 - always causes fail:
The email should have been moved to Junk Mail

Situation 2 - running eventually causes hang:
Thunderbird shouldn't hang just because it's being used.

(Sorry about the formatting - didn't notice the Markdown support, and there's no way to fix it.)

I just noticed that Thunderbird seems to generate a lot of page faults when it hangs:
http://peter.drealm.info/img/ThunderbirdPagefaults%202019-04-04%20210838.png
http://peter.drealm.info/img/ThunderbirdPagefaults%202019-04-04%20211128.png

2 million in 3 seconds.

Your first image is the crash reporter. Please post your crash report IDs here in the bug report per https://support.mozilla.org/en-US/kb/mozilla-crash-reporter-tb#w_viewing-crash-reports

Hi - all of these are the same freezes (i.e. one of the two scenarios):
bp-dccf00cc-3ec1-446f-88ed-904940190404 20 hours ago
bp-cdf699d7-becc-42fd-b116-e5b5a0190404 22 hours ago
bp-9f24217d-a2d4-4512-a243-d1e820190404 23 hours ago
bp-c1087eb7-3b77-415c-af6c-8b1330190403 2 days ago
bp-08f749a8-7c76-40d9-82a1-757bd0190403 2 days ago
bp-50ef7f64-3fee-4e08-a911-4dc520190402 3 days ago

Do you have any RSS accounts?
(and if you do anything, don't remove them, just stop the checks for new feed articles)

The variety of crash signatures suggests possible memory corruption

bp-dccf00cc-3ec1-446f-88ed-904940190404 @ OOM | small
bp-cdf699d7-becc-42fd-b116-e5b5a0190404 @ nsMsgDatabase::ClearHdrCache
bp-9f24217d-a2d4-4512-a243-d1e820190404 @ OOM | small
bp-c1087eb7-3b77-415c-af6c-8b1330190403 @ shutdownhang | NtReadFile
bp-08f749a8-7c76-40d9-82a1-757bd0190403 @ mozilla::mailnews::MsgDBReporter::CollectReports bug 1353704
bp-50ef7f64-3fee-4e08-a911-4dc520190402 @ mozilla::mailnews::MsgDBReporter::CollectReports ""

(In reply to Wayne Mery (:wsmwk) from comment #4)

Do you have any RSS accounts?
(and if you do anything, don't remove them, just stop the checks for new feed articles)

Yes, two - one to a local server that was running, one to a remote server that I'd already paused.

I've now paused all updates.

Here's another three crash reports. The most recent two were after periods of just leaving it idle, with the latest one having disabled RSS for the complete session.

bp-68670011-05e4-4ca6-a589-84ae80190408 1 minute ago
bp-67b2f3be-f4b3-446d-8118-2b5d70190408 2 hours ago
bp-d290aaa0-80da-42ef-b176-b97f30190406 2 days ago

Earlier I got a crash that didn't capture a crash report (I forgot to grab the screen shot of the actual pop-up). I'd simply clicked on the Junk folder.

After restarting, following the latest crash, I noticed that the number of items in the Junk folder was empty and the progress bar was tracking something. Then a number appear and started growing rapidly.

I didn't realise spam was so bad:
http://peter.drealm.info/img/ThunderbirdJunkHandling%202019-04-08%20164525.png

626324 junk messages in the last 14 days..?

I'll try accessing the folder again now.

(In reply to Peter L Jones from comment #8)

I'll try accessing the folder again now.

Well, the good news is that seems to have fixed the crash on accessing Junk. It was still a bit slow, but I could access the folder, unmark as junk, mark an Inbox item as junk and have it appear in the Junk folder.

I'll keep an eye on "idle" crashes but it could have been an index corrupted on Junk, which has been repaired.

(In reply to Peter L Jones from comment #9)

I'll keep an eye on "idle" crashes but it could have been an index corrupted on Junk, which has been repaired.

And if that goes OK, I'll re-enable RSS.

So, no crash whilst idling with RSS disabled and no crash whilst idling with RSS enabled again.

I'll put it down to something wrong with Junk that's sorted itself out.

As to what, I wouldn't like to say.

I would say your issue is bug 1353704

For information, I moved (to an out-of-profile space) the following, totalling 54G of disk space:

15G     Junk
156K    Junk.mozmsgs/
968M    Junk.msf
4.0K    Junk.sbd/
15G     nstmp
24G     nstmp-1
4.0K    nstmp-1.mozmsgs/
21M     nstmp-1.msf
132M    nstmp-2
4.0K    nstmp-2.mozmsgs/
282M    nstmp-3
4.0K    nstmp-3.mozmsgs/
299M    nstmp-4
0       nstmp-4.msf
4.0K    nstmp.mozmsgs/
441M    Trash
73M     Trash.mozmsgs/
8.0M    Trash.msf
12K     Trash.sbd/

On start up, Thunderbird was fully responsive and I've had no further crashes.

So how much spam are you getting daily?
Does your mail provider offer a spam filter?
And was right+click on Junk/Spam folder and Empty Junk not working for you ?

It's impossible to tell from your screen shot if http://peter.drealm.info/img/ThunderbirdCacheEntries%202019-04-04%20192104.png
is the old cache storage or cache2, the newer storage. Can you clarify please?

Also, you should attach further screen shots directly to the bug report

(In reply to Wayne Mery (:wsmwk) from comment #14)

So how much spam are you getting daily?

I've had four emails since 21:30 (local) on 30th April. This is about the rate I'd see new ones appearing generally.

Something happened in March, by the look of it -- I keep monthly backups.

2019-02-27's figures were:

1.4G    Junk
152K    Junk.mozmsgs
177M    Junk.msf
4.0K    Junk.sbd
435M    Trash
73M     Trash.mozmsgs
8.3M    Trash.msf
12K     Trash.sbd

By 2019-03-27, that had become:

15G     Junk
136K    Junk.mozmsgs
1.3G    Junk.msf
4.0K    Junk.sbd
438M    Trash
73M     Trash.mozmsgs
8.2M    Trash.msf
12K     Trash.sbd

I'm pretty sure it happened around the end of the month, too, which could tie in with

Version 60.6.1, first offered to channel users on March 25, 2019
Due to changes in the Mozilla platform profiles stored on Windows network shares addressed via drive letters are now addressed via UNC

Does your mail provider offer a spam filter?

Irrelevant - I want all email that's sent to my email address, not to have it filtered before I get it. So that's how I have my mail provider configured.

And was right+click on Junk/Spam folder and Empty Junk not working for you ?

No - this would hang / crash when I finally tried it. I guess the nstmp things come from these fails as they weren't there before, as far as I remember.

It's impossible to tell from your screen shot if http://peter.drealm.info/img/ThunderbirdCacheEntries%202019-04-04%20192104.png
is the old cache storage or cache2, the newer storage. Can you clarify please?

Also, you should attach further screen shots directly to the bug report

Ignore the screenshot -- the details are in comment #13 and here.