Note: You can also use scanPST to check and fix your OST files. After you do that, close the old PST file (Right-click the top-most folder of the PST, then select “Close”) and start using the new one. In this case, you should create a new PST file and copy all items from the old PST into the new one. ScanPST will tell you that there are no more errors, but you would still experience issues. In some cases, a corruption might be so bad that ScanPST is unable to fix it. Run ScanPST repeatedly, until it reports that there are no more errors. Important: In many cases, ScanPST requires more than one pass to fix a corruption. Microsoft is aware of this issue and provides a tool to fix it – Inbox Repair tool (scanpst). Follow the steps listed in that Microsoft Knowledge Base article to run ScanPST. For other account types, follow this section. Follow the next section – “Corrupted OST file”.

If you have an Exchange (or Office 365) account, you have an OST file. Corrupted PST fileīy far the most common reason for Outlook crashes, instability and unexplained weird behavior is a corrupted PST or OST file. If you are experiencing issues with your Outlook, try these items one-by-one and hopefully one of them will help.

This article describes some of the most common reasons that cause Outlook to become unstable, crash, hang or freeze.