An Outlook PST file can sometimes become inaccessible and display errors such as “Outlook.pst cannot be accessed,” “Errors detected in the file,” or “The file is not a personal folders file.” These problems can occur because of file corruption, oversized data files, damaged headers, interrupted write operations, or other issues affecting the PST structure.

The first step should be to make a copy of the original PST and avoid repeatedly modifying the source file. Microsoft Outlook includes the ScanPST utility for repairing data files, but there are situations where the built-in repair process may not resolve the problem or may not recover all accessible mailbox items.

For more serious PST corruption, a dedicated PST recovery tool can scan the file and provide a preview of the recoverable data before saving it. SysInfo PST Recovery Tool offers three recovery modes: Standard, Advanced, and Deep. These modes are intended for different levels of PST corruption, with Deep Recovery performing a more thorough scan when the simpler modes are insufficient.

The software can recover mailbox items such as emails, contacts, calendars, tasks, journals, and notes. It also supports selective recovery, allowing users to choose particular folders or mailbox items instead of saving the entire recovered archive. The original folder hierarchy can be maintained during the recovery process.

Another useful option is the recovery snapshot. SysInfo PST Recovery allows a recovery snapshot to be saved and loaded later, which can avoid rescanning the same PST from the beginning. The tool also provides search filters for locating specific messages or mailbox items and can generate a recovery log in TXT format.

For large PST files, the product page states support for files up to 80 GB and provides recovery options for encrypted PST data. It supports both ANSI and Unicode PST formats.

If Outlook cannot open a PST, the safest workflow is to preserve the original file, try the standard repair option first, and then consider specialized PST recovery if the problem remains.PST Repair Tool – Recover Corrupt Outlook PST