1. Corruption of PST file can be caused by virus infection or human or software errors specially when the file is opened and modified incorrectly.
2. Improper shutdown of the system before exiting the Outlook application.
3. It also happens when the PST exceeds the size of 2GB. When this error happens, the PST file cannot be found and Outlook will not synchronize.
4. If if can't overcome .pst corruption manually, then make use of https://www.repairtoolbox.com/outlookrepair.html Outlook Repair Toolbox