Outlook won't open: how to recover a corrupted PST file

When the Outlook data file (PST) gets corrupted, Outlook usually stops at the splash screen or warns that it cannot open the set of folders. The email is almost always still inside the file; what broke is part of the structure that tells Outlook where each item lives.

Signs that this is your problem

• "Cannot start Microsoft Outlook. Cannot open the set of folders."
• "Errors have been detected in the file .pst" when Outlook starts.
• "The file .pst is not a personal folders file."
• Outlook opens, but folders look empty or the program freezes when you click them.

Why it happens

• Outlook was closed in the middle of a write (power cut, freeze or forced shutdown).
• The file got close to the size limit (50 GB by default) or is an old ANSI-format PST, which breaks near 2 GB.
• The PST was on a network share, a USB drive or a cloud-synced folder.
• The disk has bad sectors.

How to fix it, step by step

1. Close Outlook and check in Task Manager that OUTLOOK.EXE is no longer running.
2. Find the file: in recent Outlook versions it is usually in Documents\Outlook Files. Control Panel > Mail > Data Files shows the exact path.
3. Copy the PST to another folder or another disk. Every repair should start from that copy.
4. Run ScanPST (the Inbox Repair Tool), found in the Office folder, for example C:\Program Files\Microsoft Office\root\Office16\SCANPST.EXE. Repeat until it finds no more errors.
5. If ScanPST freezes, finds no errors or Outlook still won't open, load the copy into the free Neural Mail Repair scan and check in the preview which folders and messages come back.
6. Save a new PST and open it in Outlook with File > Open & Export > Open Outlook Data File. Only delete the old file after you've checked your email.

How to keep it from happening again

• Close Outlook before shutting down the computer.
• Keep the PST under 20 GB by archiving old years into separate files.
• Keep the PST on the local disk and back it up with Outlook closed.

Menu names may vary with your Outlook and Windows version. Before any repair, make a copy of the data file with Outlook closed.

No software recovers 100% of cases. Overwritten parts, empty files and files encrypted by ransomware have nothing left to recover, and the free preview shows you that before you pay.