A while back, I started using Thunderbird as my email reader. After a recent "upgrade", I have had all kinds of problems.
Crashes, missing messages, corrupted messages, duplicate messages, phantom placeholder messages (i.e., messages in my inbox with no content, that exist after a duplicate message is copied to another folder), etc.
Recently, I purchased an airline ticket. The email confirmation came to my inbox. Then I received a rather strange message. It was from someone who wanted to meet me for lunch sometime. But, the message began with his signature (i.e., no content), then continued with copies of the messages we had been sending back and forth (quoted and attached to the end of his email), and then continued with the email confirmation of my airline ticket!
At first, I thought I had screwed up, and accidentally sent him my airline email confirmation. But then he would have taken this, attached it to the end of another email I had sent him, and responded to it, with no message, just a signature? That made no sense. All this took place on my work computer. So I got home, read email there (all of this is using IMAP), and his message came through no problem - actual content included, no email airline confirmation attached.
So, the way I look at it, there are two possible culprits here. Thunderbird, my email reader, and gmail, the email provider in question. I'm looking cross-eyed at Thunderbird right now. Any thoughts?