Thunderbird hangs when moving messages to sent and other folders

Question

Now and then (sometimes once a week - sometimes multiple times per day) Thunderbird looses the ability to move messages to folders. Typical symptoms are:
Send a message - message sends fine - then it hangs forever with the dialog box saying that it is copying the message to the sent folder. (I have allowed this to sit for hours - it never completes.)
If I cancel copying it to Sent, it wants to copy to Drafts - but it hangs doing that too.
Filters that move messages don't work.
The mail archiving feature doesn't work. (no error message no hang - simply does nothing.)
Junk controls mark messages as junk but don't move the messages to the junk folder.
All of the above can be remedied by simply shutting down Thunderbird and restarting it. Then it will be fine for anywhere from 5 hours to 20 days before this occurs again.
I am using a pop account with local folders. All of these moves are local to my PC. I have only been using Thunderbird for a few months so all of my folders have small numbers of messages. My drafts folder typically has zero messages (and the file is zero bytes) and it still can't copy to it.
I am running Windows 7 64 bit - installed about 3 months ago, Thunderbird 24.6.0. (The problem occurred with the previous version of Thunderbird as well.) Lots of available disk space.
Some non-default settings: Thunderbird is set to use a global inbox (local folders) and the local folders have been relocated from the default location to my user directory on drive D: TB is set to not check for email automatically or on startup. There are two accounts.
I'm using the enigmail, quicktext and allow-html-temp extensions. Though I have typically not used any of these around the time that it starts hanging. Since it can take weeks to appear, it's difficult to run safe mode or extension-less for such long periods.

Answer 1

No.
I recently had a period of about a month without it. And another time it was once a day for 3 days. (People in other threads have said it happens to them multiple times per day.) Right before the long period without the problem I had an enigmail update and I thought that that might have cured it since it worked for so long, but then it came back.
I was going to try the 31x series but early comments about it made me put that off. I'm still on 24.6. I browse the release notes now and then and see no mention of fixes for this and I've read a few other threads on the problem but haven't yet seen anyone claim that he found a fix that worked for a significant amount of time.
By the way, my first indication that this had occurred again was that I checked for email and all my spams stayed in my inbox. So I restarted TB, ran the junk controls, and they all moved to the junk folder. There is no consistency on which folder is being accessed when the problem is first seen. And there is never any need to rebuild anything to get it working again. TB just occasionally looses the ability to move messages in general. Once it happens, you can't move any message anywhere. Until you restart TB and the all is fine again. Until next time. All of this in on POP so this is just moving data around local files.