PST too large: how to deal with Outlook's 50 GB limit

Current Outlook PST and OST files have a default limit of 50 GB. Near it, Outlook slows down, search fails and, once the ceiling is hit, the file stops accepting new messages. Very large files are also more likely to get corrupted.

Signs that this is your problem

• "The file has reached its maximum size" when receiving or moving messages.
• Outlook takes minutes to open or freezes when searching.
• An old PST from Outlook 2002 or earlier broke near 2 GB.
• PST backups take too long or fail.

Why it happens

• Years of email with attachments kept in a single file.
• An ANSI-format PST, which has a 2 GB limit.
• Deleted items that take up space until the file is compacted.

How to fix it, step by step

1. Empty the Deleted Items folder and compact the file in Account Settings > Data Files > Settings > Compact Now.
2. Use File > Tools > Clean Up Old Items to move old years into an archive PST.
3. If the file is already over the limit or corrupted, open a copy in Neural Mail Repair and save the folders into smaller files. On the Technician plan, splitting by year or by size is automatic.
4. Open the new files in Outlook and check your email before deleting the original.

How to keep it from happening again

• Create one archive PST per year.
• Save large attachments to a folder on your computer instead of keeping them in email.
• Keep the main file under 20 GB.

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.