Perfect. Thanks, Brian.

I get a data error message when I receive new mail and when I try to send. It is associated, apparently, with the Main Folder (main.PMM). It says, "Probable invalid offset in index record," and suggests that I reindex the folder. When I do, it recovers old files but the problem continues to happen. The receiving error happens when when I shut down "New Mail" so that the viewed messages will go to the main folder. Both of these problems have been happening for several weeks and I have just lived with it for now.

But another problem just started happening a couple of days ago. Now, every day when I turn on my computer and open Pegasus, I get the message that there is an autosaved message and asks me to open or continue. I have tried to do both, but the problem continues to persist.

Thanks for any help you can give, 

[quote user="fdavis"]

I get a data error message when I receive new mail and when I try to send. It is associated, apparently, with the Main Folder (main.PMM). It says, "Probable invalid offset in index record," and suggests that I reindex the folder. When I do, it recovers old files but the problem continues to happen. The receiving error happens when when I shut down "New Mail" so that the viewed messages will go to the main folder. Both of these problems have been happening for several weeks and I have just lived with it for now.[/quote]

Replace the existing Main Folder as follows (make a safety backup of the home mailbox directory first):

• Create a new folder named Main_Hold and copy all messages from the Main Folder folder to the Main_Hold folder.  Check a couple of message to confirm successfull copy.
• Close Pegasus Mail
• Use a file explorer to navigate to your home mailbox directory.
• Move the files main.pmm and main.pmi out of that diretory to a temporary location (to be deleted once all is well)
• Navigate to the Programs\Defaults directory of Pegasus Mail (default is C:\Pmail\Programs\Defaults
• Copy the main.pmm and main.pmi files from the \Defaults directory to your home mailbox directory
• Start Pegasus Mail
• You should see an empty Main Folder folder. 
  
• Go to Tools > Options > Basic settings and change the default mail folder to the new Main Folder using the "Select folder" button.
• Copy or Move the messages from the Main_Hold folder to the new Main Folder folder.
• That should do it. Once you have confirmed all is well you can delete the Main_Hold folder and the moved main.pmm and main.pmi files.
  

[quote user="fdavis"]But another problem just started happening a couple of days ago. Now, every day when I turn on my computer and open Pegasus, I get the message that there is an autosaved message and asks me to open or continue. I have tried to do both, but the problem continues to persist.[/quote]

Are there any messages listed when you select File > Open saved messages (or Ctrl+O)?

Regardless, with Pegasus Mail closed, use a file explorer to navigate to your home mailbox directory and delete any zero byte .PMO files. 

BTW, If you don't know where your home mailbox directory is go to Help > About Pegasus Mail then click the Info button.  The resulting display will contain an entry that shows the path.