PST Repair Tool for Outlook opens a damaged .pst or .ost with read access only and writes what it finds into a new, clean file. Outlook does not have to be installed.
PST Repair Tool and point it at the broken .pst or .ost. Outlook can stay closed. It does not even have to be installed, because the app reads the file itself.
Automatic is the default. The cheap route runs first, and the slow one starts only when damage is actually visible. Quick only stops at the fast path. Deep scan walks the entire file and also brings back mail that was deleted from a healthy archive.
The folder tree fills up with what was recovered, and that tree is the repair result itself, not a preview of the broken file. Tick the folders you want, narrow the list by date or by text, open a message and read it.
Pick one of the 6 output formats, choose a destination and start. Output goes to a .part file and is renamed only after the last message lands. An interrupted save never leaves behind a file that opens fine and holds nothing.
The free Inbox Repair Tool edits the damaged file in place. Run it twice and it overwrites the .bak it made on the previous run. Microsoft's own help forum has the case of a 30 GB archive where the repaired file and its backup ended up holding the same wrong data, with nothing to roll back to. PST Repair Tool for Outlook does not write to the source at all. It opens with read access, and the result of the repair lands in a separate file of its own. Whatever that result turns out to be worth, what you started with is still sitting there.
Deleting a message in Outlook does not wipe it from the .pst straight away. The record survives until something reuses the space. Deep scan reads those leftovers. On a test file with 11 messages deleted for good, all 11 came back, while an ordinary folder walk saw not one of them. Be realistic about it, though. Outlook reuses body blocks before anything else, so a recovered message frequently arrives with headers intact and its body gone, and we mark it that way instead of pretending.
When a repair tool cannot validate an item, the usual answer is to delete it, which is exactly why people finish a repair staring at folders that exist and are empty. Here a message whose body or attachment did not survive is still written out and marked [partial], and the note inside says what is missing. That mark comes from a loss mask the engine accumulates while it reads, not from a guess at the end.
PST Repair Tool for Outlook begins by opening the file just as Outlook would. If that works, it stops right there and reports it. If it does not, the header is rebuilt in a copy: 7 fields that actually matter, about 46 bytes. Only then does a signature sweep step through the whole file in 64-byte increments, verifying every block with CRC32. The expensive pass runs when it is needed, not by default.
The app ships with its own PST reader and its own writer for individual letters, so a computer without Office installed can still open the mailbox and pull the correspondence out. Useful when the .pst arrives on a memory stick and whoever brought it has no Outlook at all.
Two checkboxes decide whether attachments and images embedded in messages go into the output at all. A mailbox stuffed with scanned invoices gets a lot lighter when you leave them out.
Every run ends with a written rundown. It names the level that did the repair, what was found, what was written, how many [partial] items there are and, in a block of its own, what was not recovered. There are no file names in it, no subjects and no addresses, because it is meant to be pasted into an email.
A repair needs room for the working copy and for the output, so it asks for 3 times the input size and measures the smaller of the 2 volumes involved. Better a warning at the start than a dead stop at 90%.
Writing runs on a worker thread. A 10 GB mailbox takes around 17 minutes and the window stays responsive throughout. Press Stop and the unfinished .part file is deleted on purpose, so a half-written export cannot pass itself off as a working archive.
An .pst inherited from a dead laptop, from a colleague who left, from a backup drive nobody has opened in years. It refuses to attach, Outlook announces that it is not a personal folders file, and there is no second copy anywhere.
The user has already run the built-in repair twice, mail went missing somewhere along the way, and the ticket lands on you. With 6 output formats you can hand back a PST, or a folder of EML files, or a PDF, whatever this particular case really needs.
Lawyers, accountants, anybody who has to account for correspondence years later. What counts is not a cheerful success number but knowing precisely what did not come back, stated in writing.
One repair run, one destination of your choosing. The default is a fresh PST you can attach in Outlook straight away.