Comment 14 for bug 2060534

> Can't stress enough that you should attempt to trim your sent folder size. Suggest target to reduce by half.

I think you are still reacting to the inexplicit 50GB from the first screen shot.
My current size (after fully downloading the Sent folder) is 3GB.

Also, to clarify: I did not reproduce the compact issue when it creates a massive file since I deleted my entire IMapMail dir and reconstructed it.
At this point I think there was some corruption.
In general, I think at this day and age it would be better to use sqlite to store the messages instead of creating a custom flat file implementation. That would be much more robust and reliable if a bit slower.

Re virus scanner:
I disabled the realtime windows virus protection and it doesn't make a difference for the indexing.
I am also running a virus scanner on the entire mail directory in the mail server now to be sure there are no mines there that can trigger the realtime virus protection.

When I disable the indexing for the 2009 folder, Thunderbird is able to download and index everything.
At this point I can either leave it excluded, or try to hunt down the problematic message.
Is there a way to enable verbose logging for the indexer?
If not, I can probably do a binary search by moving messages around in that folder until I find the offending message.