I had the same problem as Mark with 4.76 -> 6.1 on linux. I definitely deleted all the .msf files and it made no difference. Somehow I stumbled on this fix which works for no reason I can understand. It is easy to implement this with linux:
1) My non-working mail folders were in /home/myusername/.mozilla/myusername/4gmnwu5o.slt/Mail/Local Folders/Mail/ I moved them all to /home/myusername/.mozilla/myusername/4gmnwu5o.slt/Mail/Local Folders/Mail.sbd/ 2) I created empty files (using the linux "touch" command) for every mail folder in the original /home/myusername/.mozilla/myusername/4gmnwu5o.slt/Mail/Local Folders/Mail/ so it now just has a bunch of files of size 0! Now everything appears and is found correctly in the 6.1 mail browser.The browser reads "Mail", not "Mail.sbd", even though the actual mail is in the Mail.sbd directory. The only remaining problem is that when I want to create a new folder in Mail, I have to manually go in to .../Mail/ (not Mail.sbd) and create an empty file in advance. Hope this works for you. Anyone understand what is going on? Joel
