Thunderbird Error on Upgrade to 9.04

Hello all,

I have a problem with thunderbird and I could do with some advice.

In the last few days I have just updated from 8.10 to 9.04. I migrated my thunderbird mail across by copying .mozilla-thunderbird folder. Now, I have two PCs - a lap top and a desktop which I keep in sync to back each other up. I was having problems getting duplicate mail in the inbox when I backed up thunderbird between the two machines - note this was happening before I upgraded as well.

So what I did was (after the 9.04 upgrade and still getting duplicate mail problems) I followed the instructions in link http://kb.mozillazine.org/Duplicate_messages_received. I deleted .msf folders, compacted the files and also deleted popstate.dat as recommended.

This morning I just looked at my Calendar and Tasks - they are not there - all vanished. In addition I cannot seem to enter any new tasks or any new calendar events these options are all greyed out. I don't know if the Calendar and tasks were there before I deleted the .msf files etc. - I did not check. But if I had to guess I would say they were not.

Does anyone know what is going on? I would love to get my calendar and tasks back if I can. At the very least I need to be able to add new ones. Hope you can help.

Thanks a lot.