For Windows 10 and 11 · PST, OST and MBOX
Get your email back without risking the original file.
Neural Mail Repair fixes Outlook data files (PST and OST) and MBOX mailboxes that won't open. It recovers messages, attachments, contacts and calendars, shows you everything before you pay, and never sends anything to the internet.
Launching soon. Join the list and we'll tell you first.
- The original is never changed
- Nothing leaves your computer
- Outlook not required
- Pay once
- Inbox31,540
- Sent Items12,877
- Clients 20242,106
- Contacts1,284
- Calendar405
- 718 items with unreadable blocks (listed in the report)
- Original untouched: SHA-256 verified
Seen one of these? Neural Mail Repair was built for them.
- “Cannot start Microsoft Outlook. Cannot open the set of folders.”
- “Errors have been detected in the file .pst. Quit Outlook and use the Inbox Repair Tool.”
- “The file .pst is not a personal folders file.”
- “The .ost file can't be opened: the account no longer exists on this computer.”
- “The file has reached its maximum size and can't accept new items.”
- “Messages disappeared from a Thunderbird folder (MBOX file).”
How it works
Three steps, and you see your email before you pay
- 1
Pick the file
Drag the PST, OST or MBOX into the window, or let the app find Outlook and Thunderbird files on your computer. The original is opened read-only.
- 2
See the scan and preview
The app copies the file, analyzes its structure and shows the folders, messages and attachments that come back, with anything lost clearly marked. Free, no sign-up.
- 3
Save it where you need it
With a license, save a new PST to open in Outlook, MBOX for Thunderbird, or individual messages (EML). The app checks that the original stayed the same.
The scan uses color, icon and text
- Repairable
The mailbox can open again in full.
- Partial recovery
Most of it comes back; the report shows which folders or items had unreadable parts.
- No content
There is no recoverable email data (empty, overwritten or ransomware-encrypted file), and the app tells you before you buy.
What comes back
Everything your mailbox holds
A PST or OST file is a whole database, not a document. When one part of it breaks, Outlook refuses to open any of it. Neural Mail Repair reads the file block by block, separates what is intact from what is damaged and rebuilds the mailbox with the folders in place.
Messages and attachments
Sender, recipients, dates, subject, plain-text or HTML body and the attachments of each email.
Folders and subfolders
The folder tree as it was, including folders you created yourself.
Contacts, calendar and tasks
Contacts with phone numbers and addresses, calendar appointments, tasks and notes.
Deleted items still inside the file
Deleted messages often remain inside the PST until it is compacted. When the blocks still exist, the app shows those items separately.
OST files from accounts that no longer exist
Local copies of Exchange, Microsoft 365 or IMAP accounts that Outlook won't open anymore become a regular PST.
MBOX mailboxes
Thunderbird, Apple Mail and Google Takeout exports, fixing broken separators and messages stuck together.
Inputs and outputs
- Opens:
- .pst
- .ost
- .mbox
- .mbx
- .eml
- Saves as:
- .pst
- .mbox
- .eml
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.
Neural Mail Repair is still in development. This is what the launch version will do; if anything changes before then, this page will be updated before sales open.
Why it happens
Why Outlook data files get corrupted
Almost every damaged PST comes down to one of these causes. Knowing which one helps you pick the fix and stop it from happening again.
- 1
Outlook closed in the middle of a write
A power cut, a Windows freeze, holding the laptop's power button or ending Outlook from Task Manager. The PST was being updated and was left half-written. This is the most common cause.
- 2
The file is too large
Current Outlook PST and OST files have a default limit of 50 GB (20 GB in Outlook 2003 and 2007). Near the limit Outlook slows down, stops accepting messages and the risk of damage grows. Old ANSI-format PSTs break past 2 GB.
- 3
PST on a network share, cloud folder or USB drive
Microsoft does not support opening a PST over the network. Synced folders (OneDrive, Dropbox, Google Drive) and USB drives pulled out without ejecting copy the file while it is open, mixing versions.
- 4
Bad sectors on the disk
A hard drive or SSD that is starting to fail damages the most-used blocks first, and the PST is one of the most read and written files on the computer. If the disk makes noises or Windows is slow at everything, the disk may be the real problem.
- 5
Antivirus and Outlook add-ins
Antivirus software that scans the PST while Outlook is writing, and poorly written add-ins that touch the folders, can interrupt a write and leave the indexes inconsistent.
- 6
Interrupted sync (OST)
An OST is the local copy of an Exchange, Microsoft 365 or IMAP account. An interrupted sync, a recreated profile or a removed account leaves the file inconsistent or orphaned: the email is there, but Outlook won't open it.
- 7
Migrations and manual copies
Copying the PST while Outlook is open, restoring incomplete backups or moving between Outlook versions without the right steps produces files with missing parts.
- 8
MBOX with broken separators
In Thunderbird and Google Takeout exports, every message in a folder sits in a single text file, separated by "From " lines. One broken line makes messages vanish or merge into each other.
How to prevent it
Eight habits that keep you from losing email
None of them costs anything. If you look after other people's computers, this list is worth printing.
Close Outlook before shutting down
Wait for the icon to leave the Windows tray. On a laptop, set the power button to sleep rather than to shut down instantly.
Keep the PST well below the limit
Archive by year (for example, one PST per old year) and use File > Tools > Clean Up Old Items. Below 20 GB, Outlook has plenty of headroom.
Compact now and then
In Account Settings > Data Files > Settings > Compact Now, Outlook reorganizes the file and frees the space of deleted items.
Keep the PST on the local disk
Never open a PST straight from the network, a USB drive or a synced folder. For backups, copy the file with Outlook closed.
Back up with Outlook closed
A copy made while the file is open can be corrupted from the start. Schedule backups for when the computer is idle, or close Outlook first.
Watch your disk's health
General slowness, freezes and noises are warnings. Copy the PST files somewhere else first, then replace the disk.
Review your add-ins
In File > Options > Add-ins, disable what you don't use. Less code touching your folders means less chance of damage.
Convert old (ANSI) PSTs
Files created in Outlook 2002 or earlier use the ANSI format, which breaks near 2 GB. Export the content into a new PST.
On Microsoft 365 or Exchange? The server already keeps your mailbox. The local OST can be recreated; what usually goes missing are archive PSTs that only exist on your computer.
Before you buy
Which path to take, from free to professional
- 1
Outlook reports errors in the PST, but the file is small and the damage looks light
Try ScanPST first, the Inbox Repair Tool that ships with Office. It's free. Copy the PST beforehand, because ScanPST changes the file and may discard items it doesn't understand.
- 2
ScanPST froze, found no errors, or Outlook still won't open
Use the free Neural Mail Repair scan. It doesn't change the original and shows what comes back before you decide.
- 3
The email account still exists on Microsoft 365, Exchange or Gmail
Remove and recreate the Outlook profile: the OST downloads again from the server. Only items that were never synced need repair.
- 4
The disk makes noises, disappears from Windows or the computer freezes when copying the PST
Stop using the disk. First get the files off with Neural Rescue or a data recovery lab; then repair the copy.
Why trust it
Built for people who can't afford to lose an email
The original stays untouched
The app reads the file, works on a copy and checks the fingerprint (SHA-256) at the end to prove the original didn't change.
See it before you pay
Scanning and previewing folders, messages and attachments is free. You only pay to save.
Nothing leaves your computer
Email holds contracts, client data and personal conversations. The whole repair happens on your computer.
No Outlook needed
Opens and shows PST, OST and MBOX even without Outlook installed or with a broken Outlook.
Pay once
Lifetime license for the edition, no subscription and no price that climbs at every step.
For technicians, repair shops and IT
The broken-Outlook case at your counter, solved without drama
An Outlook file that won't open is urgent: the client needs their email today. With the Technician plan you serve as many clients as you want, process several files in a queue and hand over a report with your own brand.
See the Technician planCommercial use
Serve clients and companies with no case limit, on up to 3 computers at your bench.
File queue
Queue several PSTs and OSTs to scan and save in sequence, without watching the screen.
Client report
A PDF with what was recovered, what was lost and the file fingerprints, with your shop's logo.
Split large PSTs
Save the result in smaller files, by year or by size, so the client's Outlook has room to breathe.
Pricing
Free scan. Pay once to save.
Lifetime license per edition: buy the 2027 edition and use it forever, with free fixes released during the year. No subscription and no hidden editions.
2027 edition · Prices in USD, based on your country.
Free
To find out whether your mailbox can be fixed.
- 1 computer
- Scan PST, OST and MBOX
- Preview folders, messages and attachments
- Save up to 50 items to check the result
Personal
SelectedFor your own mailbox, with no limit.
- 2 computers
- Unlimited saving
- PST, OST and MBOX
- Save as PST, MBOX or EML
- 2027 edition updates
Technician
For repair shops, technicians and IT teams.
- 3 computers
- Commercial use, unlimited clients
- Queue several files
- PDF report with your brand
- Split large PSTs
Upgrade
Coming soonFor owners of the previous edition moving to the new one.
Available when the 2028 edition is released.
- 2 computers
- Everything in the new edition
- Keeps your plan
Secure payment. 7-day refund, no questions asked.
Credit card, processed by Stripe.
Sales open at launch. Join the waitlist and you'll hear first, no strings attached.
Get notified at launch
Neural Mail Repair is in development. Leave your email and we'll let you know as soon as the app is ready to download.
Same family
When the problem isn't email
Neural Repair
Word documents, Excel spreadsheets, PDFs, zip files, photos and videos that won't open.
Neural Rescue
Files stuck on a failing hard drive, USB drive or memory card, or deleted by mistake.
Frequently asked questions
Does Neural Mail Repair recover any PST file?
No software recovers 100% of cases. The app recovers as much as possible and shows you first, for free, what comes back and what was lost. If the file is empty, overwritten or encrypted by ransomware, there is no email to recover, and the app tells you so.
Is my original file at risk?
No. The app opens the original read-only, works on a copy and checks at the end, using its SHA-256 fingerprint, that not a single byte of the original changed. Even so, we recommend keeping a copy of the file before any repair.
Do I need Outlook installed?
Not to scan, preview and save. To open the repaired PST and keep using your email, you'll need Outlook (or Thunderbird, if you save as MBOX).
Is my email sent to any server?
No. The whole repair happens on your computer. The internet is only used to activate the license, and activation sends no email, file name or content.
How is it different from Microsoft's ScanPST?
ScanPST is free and handles light damage, but it changes the file itself, may discard items it doesn't understand and doesn't work with orphaned OST files or MBOX. Neural Mail Repair works on a copy, shows what comes back first, opens OST files from accounts that no longer exist and saves to other formats. It's worth trying ScanPST first, on a copy of the file.
Can I open an OST from an account that was deleted?
Yes, if the file is on your computer and you have the right to access that mailbox. The app converts the OST into a regular PST that Outlook opens as a data file. Messages protected by encryption (S/MIME or information rights protection) stay protected: they only open with the original certificate or permission.
What if the PST has a password?
The app asks for the password. Neural Mail Repair does not crack or remove passwords: it was built to recover mailboxes you already have the right to open.
My PST is over 50 GB. Can the app handle it?
Yes. It reads files above Outlook's limit and, on the Technician plan, saves the result split by year or by size. On the Personal plan you can save chosen folders into separate files.
Does it work with Thunderbird, Apple Mail and Google Takeout?
Yes, they all use MBOX. The app fixes broken separators, recovers messages that vanished from a folder and can save the result as PST to take it into Outlook.
Does it work on a Mac?
For now, Windows 10 and 11 (64-bit) only. Mac files (such as MBOX exported from Apple Mail) can be copied to a Windows PC and opened there.
What does "lifetime per edition" mean?
You pay once and use the edition you bought forever, with its fixes. When next year's edition comes out, you decide whether to upgrade at the upgrade price.
What if I change my mind?
You have 7 calendar days to ask for a full refund, no questions asked. Where your country's law gives you longer, the legal period applies. Details are in the refund policy.
Can I use it in my repair shop or company IT?
Yes, with the Technician plan, which allows commercial use and includes the file queue and a report with your brand. Only use it on mailboxes the client or company has authorized you to access.
Your email may well come back. Find out for free.
Scan and preview at no cost, with no sign-up and nothing sent to the internet.
Join the waitlist