If removing the index file *.pmi, and trying to re-index the actual folder doesn't work you will need to rebuild the actual folder. But first take a look at the size of the Main Folder. If its size is anything bigger than about 1 Gb you will be in danger of exceeding the filesize limit on the operating system.
If you download my utility, NotSplit from the Community download area, you can recover the individual notes (with their associated attachments).
NotSplit is located at url: http://community.pmail.com/files/folders/utils/entry3962.aspx
Some guidelines:
1. Write down the actual folder file name (*.pmm)
2. Find out the New Mail folder (actually just a directory), and note its location (ie: c:\pmail\mail\<username>) Use Pegasus Mail\help\About menu and click on Info button to get location
3. Empty out the content of the New Mail folder by copying its content to a temporary folder.
4. Delete the messages in the New Mail folder. Folder should now be empty.
5. Extract NotSplit.exe from the downloaded Community file mentioned above.
6. Run the program NotSplit.exe. It will probably take some time to extract all the messages from the *.pmm identified in point 1. above into the New Mail folder.
Rename the folder file identified in point 1. to something like *.pmm.txt This is your original folder in its current (broken) form
7 Look at the New Mail folder in Windows Explorer or equivalent. Its size should not exceed the 1 Gigabyte limit. If it does, you will need to do some work on the New Mail folder.
8. If the answer to 7. is too big, then set up a number of working directories under your Temp directory, ie c:\temp\a c:\temp\b c:\temp\c etc
9 Cut & Paste a group of about 500 messages from the New Mail directory into one of these working directories
10. Repeat item 9. above but change the target directory, until your New Mail directory is empty
11. Select & MOVE a group of about 500 messages from a target directory (ie c:\temp\a) into the New Mail folder(ie c:\pmail\mail\<username>)
12. Start Pegasus Mail. Look at the New Mail folder in Pegasus Mail, and you should see these messages with their attachments.
13. In Pegasus Mail, Create a Pegasus Mail folder, then Select & MOVE these New Mail messages to the new folder
14. Repeat points 11 to 13 above
15. At this stage all of your messages have been recovered. Take a break :-)
If you have any mail messages that are VERY large (ie 10+ Megabytes (eg: photo albums or video or music collections) , you should MOVE them to a temporary folder.
All that is left to do, is arrange these folders by function. This will likely cause you to assign every message. Very time consuming.
Let me know if you need more advice. Good luck !!
Martin