Crash report: https://crash-stats.mozilla.org/report/index/e8046dd0-2a8d-45ab-8830-e63420201006

Reason: EXCEPTION_BREAKPOINT
MOZ_CRASH Reason: MOZ_CRASH(Shutdown hanging before starting.)

Top 10 frames of crashing thread:

0 xul.dll morkWriter::WriteAllStoreTables comm/mailnews/db/mork/morkWriter.cpp:982
1 xul.dll morkWriter::OnStoreRowSpacesTables comm/mailnews/db/mork/morkWriter.cpp:1024
2 xul.dll morkWriter::WriteMore comm/mailnews/db/mork/morkWriter.cpp:323
3 xul.dll morkThumb::DoMore_CompressCommit comm/mailnews/db/mork/morkThumb.cpp:429
4 xul.dll morkThumb::DoMore comm/mailnews/db/mork/morkThumb.cpp:323
5 xul.dll morkThumb::DoMore comm/mailnews/db/mork/morkThumb.cpp:143
6 xul.dll nsMsgDatabase::Commit comm/mailnews/db/msgdb/src/nsMsgDatabase.cpp:1378
7 xul.dll nsMsgDatabase::CloseMDB comm/mailnews/db/msgdb/src/nsMsgDatabase.cpp:1281
8 xul.dll nsMsgDatabase::ForceClosed comm/mailnews/db/msgdb/src/nsMsgDatabase.cpp:1301
9 xul.dll nsMsgDBFolder::Shutdown comm/mailnews/base/src/nsMsgDBFolder.cpp:235

78.3.1 (64-bit)
Windows is managing the page file.

https://hg.mozilla.org/releases/comm-esr78/file/tip/mailnews/db/mork/morkWriter.cpp#l982 shouldn't be able to crash.

Perhaps your crashes are McAfee related.

Do you have McAfee set to exclude Thunderbird executable and profile directory?

(In reply to Wayne Mery (:wsmwk) from comment #3)

Do you have McAfee set to exclude Thunderbird executable and profile directory?

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

(In reply to Wayne Mery (:wsmwk) from comment #3)

Do you have McAfee set to exclude Thunderbird executable and profile directory?

I just did that now.

SIDE NOTE:
In doing the above, I noticed that even though I have the 64 bit Thunderbird, that there is a directory
C:\Program Files (x86)\Mozilla Thunderbird
but not one in C:\Program Files
Shouldn't that be the other way around?

(In reply to Worcester12345 from comment #5)

...
In doing the above, I noticed that even though I have the 64 bit Thunderbird, that there is a directory
C:\Program Files (x86)\Mozilla Thunderbird
but not one in C:\Program Files
Shouldn't that be the other way around?

No, installing in (x86) is intentional - installing in the other directory would cause problems for a user related to https://support.mozilla.org/en-US/kb/dedicated-profile-thunderbird-installation

Changing severity to S4 because crash is rare

Sorry, putting back to "OS: All". I thought I had mistakely put that.

Given the low crash rate - 5 per week for version 91 - I don't think we're going to spend any time tracking or debugging unless someone comes forward with steps to reproduce.