I have Outlook (maybe an old version, I can't tell how to find the year) on a fairly new Windows XP Home computer. When I start up and try to open outlook I get an error message

Cannot start Outlook, unable to open your default mail folders. File c:\ outlook\Rockey.pst is not a personal folders file.

I have searched the messages and cannot find this one. Any suggestions?

I did figure out that the system restore wouldn't do it, also saw on Microsoft that there were updates for 2002 regarding the files being too big and not getting a warning before it died. My husband decided to take the computer in for service, he uses it for a lot of work and really needed a solution...saves me a lot of trips up and down the stairs . Thank you so much for your help.

It is outlook 2002, has been having trouble with email for a while. I changed to show hidden files and can only find one file that is Rockey.pst in oultook and it says it is 0 KB and modified 3/24/2007. Should I do a system restore and go back to when it was working? It is actually my husband's computer, we are both beginners as far as computer knowledge , but I am the one going up and downstairs from my computer to his. Thanks for your help.

A System Restore will not restore the Outlook "Rockey.pst" as it is a "data" file and not a Windows system file.

That it has 0 bytes indeed suggests it is corrupt.

Ideally all data files should be backed up, including the .pst files for eventualities such as this. Reinstalling Outlook would create a new (empty) file that would be recognised, it is unlikely that the old corrupt one will be easily recoverable.

Did it contain any critical data? If not, reinstall Outlook 2002.

Another method would be to make a copy of your .pst file, rename it and replace his with it. That way he will have a valid pst file with all your emails and contacts. Or would that be a danger....

The .pst file is where Outlook stores all emails, contacts and attachments.

Normally it is called Outlook.pst but can be personalised by name via Outlook.

It sounds like your PST file has become corrupt (this can easily happen when they get too large) and is not being recognised, so Outlook will not open.

There are utilities to repair corrupt psy files, but knowing the Outlook version would help.

The first thing to do would be to take a copy of the "rockey.pst" file in case it is recoverable and save it elsewhere.