I ran into a most troubling problem last night. When I opened Thunderbird, my In Box would not display. This is not the first time this has happened, so I figured that another version of the software was still running. Unfortunately, that turned out not to be the case.
I did some digging and found this very detailed article in the MozillaZine Knowledge Base, which provides some great information and a slew of possibilities for solving this problem. I tried the ones applicable to my situation, but my feeling was that the In Box index file (.msf) was corrupted. I also learned that you need to compact your In Box from time to time using the File > Compact Folders command.
I deleted the In Box msf file by following the path:
C:\Documents and Settings\Ron\Application Data\Mozilla\Profiles\Ron\v2expugz.slt\Mail\mail.comcast.net
I even deleted the In Box file itself (I kept a backup; I'm not completely crazy) with the hope of at least starting over and worrying about the corrupt file another day. Yet the In Box didn't go away, and it didn't rebuild itself as it was supposed to. Curiouser and Curiouser.
At one point, I actually got into the In Box, and was able to *see* my email, but when I tried to open an email, it was blank. What's more, I could send an email just fine and see the contents of my sub-folders. This was a problem strictly the related to the In Box. That much I understood.
At this point, I was so desperate, I even resorted to spending $40 to call Mozilla.org's paid support hotline, but when I told the support guy what steps I had taken, he said that's exactly what he would have done and didn't charge me for the call (mercifully).
Then I found it...
I turns out that the profile in the Mozilla folder was an OLD profile. So by deleting the msf, I wasn't doing anything, which is why nothing changed after I did it. My ACTUAL, working profile was in Application Data/Thunderbird folder. So all along, I was working off the wrong file. When I deleted the msf file in the correct folder and reopened Thunderbird, the system rebuilt itself just as it should and all was right with the world, but I had to go through some major aggravation before I figured this out.
And I hope by posting this, that at least some of you out there can benefit from my experience and not face the anxiety that I did trying to resolve this.