When opening a damaged or corrupt Outlook PST file with Microsoft Outlook, you see the following error message:
Errors have been detected in the file xxxx.pst. Quit Outlook and all mail-enabled applications, and then use the Inbox repair tool(Scanpst.exe) to diagnose and repair errors in the file. For more information about the Inbox repair tool, see Help.
where ‘xxxx.pst’ is name of the Outlook PST file to be opened.
Below is a sample screenshot of the error message:
The PST file is composed of two parts, the file header, and the following data part. The file header contains the most important information about the whole file, such as the file signature, file size, compatibility, etc.
When Microsoft Outlook is trying to open a file, it will first read the header part and verify its information, for example, the file signature as well as the compatibility information. If the verification fails, it will report the “The file xxxx.pst is not a personal folders file.” error. Otherwise, it will continue reading the remaining data part and if there are any errors in that part, it will report the above mentioned error, and suggest you to use the Inbox repair tool(Scanpst.exe) to fix it.
Sample corrupt PST file that will cause the error. Outlook_2.pst