Common Signs of PST/OST File Corruption
Typical symptoms of damaged Outlook archives include: - Outlook error: "Errors have been detected in the file <filename>.pst. Quit Outlook and all mail-enabled applications, and then use the Inbox repair tool (Scanpst.exe)." - In-browser parser message: "Invalid header or unexpected end of file." - File size reported as 0 KB or sudden truncation after an unexpected system shutdown.
Step 1: Verify Archive Size and Integrity
Before attempting complex recovery: 1. Verify the file size on your local disk. If the file is under 256 KB, it may be an empty placeholder without messages. 2. Check if the file is locked by a running instance of Microsoft Outlook or OneDrive sync. Close Outlook completely before opening the file in any reader.
Step 2: Try Microsoft’s Free Inbox Repair Tool (ScanPST.exe)
If you have Microsoft Office installed on a Windows machine:
1. Locate scanpst.exe in C:\Program Files\Microsoft Office\root\Office16\.
2. Browse to your damaged .pst file.
3. Click Start to scan the B-Tree hierarchy and repair low-level block descriptor discrepancies.
Step 3: When Browser Viewers Reach Their Limits
In-browser viewers parse archives inside your browser's JavaScript memory heap. If an archive has severe structural sector damage or exceeds available system RAM, in-browser decoders cannot reconstruct missing B-Trees. In such cases, specialized offline desktop recovery software can read raw data blocks and reconstruct recoverable folders into clean new archives.