Thunderbird version 38.7.2 MacBook Pro OS X version 10.11.5 Open Thunderbird, some emails load, but I can't click on any, and I very soon thereafter get spinning wheel and am told program "not responding". I have 3 different email addresses coming into Thunderbird (all IMAP). I'm able to go to all 3 online and read/delete etc. emails. Had this problem in past and was able to delete .msf files in my Thunderbird profile on my computer (research showed that they sometimes become corrupt?) I've tried again this time, but it hasn't worked.