Ever since I upgraded to Lion from SN, I have had problems with Lion Mail app.
At first, it couldn't find my messages so I learned about rebuilding the mailboxes and it helped.
Then I lost about 600 messages from Sent of one of my two accounts (not all sent emails were gone but about 600). I restored them from Time Machine and blamed my two year old.
Now again, I cannot find the darn message and I know it is there as I had to manually scroll through to find it. I ran "Rebuild" but it didn't do a thing. I removed Envelop Index from ~/Library/Mail/V2/MailData but even after indexing the search still doesn't work!
If I use token "From:" and "company.com" it finds it but not if I am looking for just "company". This drives me nuts to the point that I am ready to smash my MBP to smithereens.
I've had a few failed searches in the past that I cannot remember of but I know it took me extra time to locate the messages. I'm trying to get used to the way Apple rethought I have to use my Mail now but sometimes I just don't have that kind of time.
Q1. Will anything change in ML Mail?
Q2. I use Thunderbird for my personal accounts and don't want to mix work and home (sometime I accidentally send emails from the wrong accounts). Can I have 2 Thunderbird apps running at the same time on one machine?