Last reviewed on July 31, 2015   —  10 Comments

Microsoft Outlook limits the size of older Personal Folders .pst files and offline folders .ost files to 2GB. If a new or changed item increases the size over than limit, you will not be able to use the .pst or .ost file. Even if you delete items from the server mailbox, the .ost file will not synchronize.

Beginning with Outlook 2003, larger PST files are supported. However, if you upgrade from an older version you need to create a new PST, the older PST format is not automatically converted or upgraded. See Convert an old PST to a Unicode PST. If the old PST won't open in Outlook you will need to repair it before you can convert it.

Shrinking a file that’s over the limit | Preventing files from growing too large
Other Tools | More information

How to check the data file (pst) format

Right click on the top level folder and choose Properties (Data File Properties in Outlook 2010)

Click Advanced to open the data file dialog.

If the data file is listed as “Outlook Data File” and you are using Outlook 2003 and up, its a Unicode data file.

If the data files is called “Outlook 97-2002 Data File” its an older ANSI format and is limited to no more than 1.9 GB in size and no more than 65,000 items per folder (often less).

Outlook Data File Properties

Shrinking a file that’s over the limit

Outlook has no built-in way to reduce a PST or OST file that has gone over the limit. However, Microsoft provides a tool, PST2GB, which you can download to restore the file to operability. Note, however, that the utility truncates the data from between 25 and 50mb and the truncated data is not recoverable. The remaining data under 2GB should be restored. See OL: Oversized PST and OST Crop Tool for more information.

If you want to attempt repairs yourself, use a tool called a hex editor to edit the data in the file directly. Every Windows shareware site has a selection of hex editors. Eugene McCarthy of FAO Headquarters in Rome recommends the free iHex editor, which loads only 64kb of the file at a time, making it ideal for tinkering with extremely large PST files.

Make a backup of your PST or OST, then open the original file with the hex editor (available for download from any Windows shareware site). You’ll want to remove a few characters from the middle of the file, then save it and try to run the Inbox Repair Tool (Scanpst.exe) to repair the damage you did with the hex editor. If Scanpst can repair the file, you should be able to open it Outlook again. If not, try removing some additional characters from the file.

If this process works, with any luck, you’ll lose only one or two items. You may be able to recover 100% of the data by repeating the process with a new copy of the file, but removing the data from a different area.

Preventing PST files from growing too large

Beginning with Microsoft Office XP Service Pack 1, Outlook provides better protection against Personal Folders .pst and offline folders .ost file growing past the 2GB size limit. Once an PST or OST file reaches 1.82GB, users will not be able to add new items.

These MSKB articles contain more information:
Mail Delivery to Inbox Stops When the Personal Folder or Offline Folder Is Full
Error Message Copying File to PST That Exceeds 1.82 GB

Office 2000 Service Release 1/1a updates Outlook 2000 so that you cannot add more data as the PST or OST size approaches 2GB; this prevents corruption, but the user gets no warning.


Tools in the Spotlight

DataNumen Outlook Repair

DataNumen Outlook Repair is a powerful tool to repair and recover corrupted Outlook PST files. Main features: recover mail messages, folders, posts, appointments, meeting requests, contacts, distribution lists, tasks, task requests, journals and notes in PST files; support to recover attachments; support to recover deleted Outlook items; support to recover oversized 2GB PST files; support to split the output PST file into several small ones; support to recover password protected PST files; support to convert PST file from Outlook 97-2002 format into the new Outlook Unicode format.

Kernel for Outlook PST Repair Tool

Kernel for Outlook PST Repair Tool recovers and restores emails and other items from damaged, corrupted or broken PST files. The demo version shows you exactly that how many emails and other items will be recovered using the full Kernel Repair PST Software. Kernel for Outlook PST Repair supported versions are Outlook 97, 2000, XP, 2003. It successfully recovers all items from the PST file including emails, drafts, calendars, journal, notes, tasks, contacts etc. OST repair tool available.

Stellar Phoenix Outlook PST Repair

Outlook PST Repair software repairs the corrupted PST file and for recovering its entire mailbox items. This software even repairs file which are larger than 2 GB and also recovers deleted emails. Stellar Phoenix Outlook PST Repair software has several powerful features like repair password protected and encrypted files and also recovery of selected folders. This software works with almost all latest Outlook versions and has good compatibility with Windows 8, 7, vista, 2003, 2002 and 2000.



CopyPST repairs Outlook data files by exporting it to a new file, ignoring any error. It requires that the data file can still be opened in Outlook. Exporting a file breaks links, which can be repairs using OLfix program. Free

DataNumen Outlook Drive Recovery

Outlook Drive Recovery can recover all Outlook data from drives or disks, including messages, folders, posts, appointments, meetings, contacts, distribution lists, tasks, journals and notes. All properties, such as subject, to, from, cc, bcc, date, etc., are recovered. Recover Outlook data with password protection, both compressible encryption and high encryption. All drives and file systems supported, including hard disks, flash drives, Zip disks, CDROMs, etc., and any file systems, such as FAT, FAT32, NTFS, Linux Ext2, Linux Ext3, etc.

Disk Doctors Outlook Mail Recovery (.pst)

Disk Doctors Outlook Mail Recovery (.pst) efficiently recovers messages, folders, appointments, meeting requests, contacts, tasks, task requests, journals and notes from .pst files. Mails are recovered in plain text, HTML and RTF format. The software has advanced support to recover large attachments and embedded HTML messages. It also supports recovery of password protected .pst files and both compressed encryption and high encryption .pst files. The software creates a new healthy .pst file from a corrupt .pst file.

Easy Mail Recovery

The software enables the recovery of deleted messages and messages from corrupted Microsoft Outlook and Microsoft Outlook Express data files. Messages, attached files, contacts and notes can be viewed, saved in the EML/VCF/TXT format and later imported into the mail client. The program uses original algorithms that assist in the recovery of a maximum number of messages even if the mail client cannot open the message database.

EasyRecovery EmailRepair

Repair corrupted .pst and .ost files and those exceeding the 2gb limit. Retrieve deleted items from Outlook folders. Can access password-protected .pst files. Can also repair and restore Outlook Express data.

Exchange 2000 Tool: PST2GB

Support tool used to create a truncated copy of a .pst file which allows some recovery when the file size has reached over 2 gig. The copy does not have all the original data because the tool cuts a user defined amount of data from the file. See KB 296088.


BackOffice Resource Kit utility that can identify which mailboxes contain messages meeting certain criteria, such as a virus-infected file attachment. See XADM How to Find Mailboxes That Contain a Specific Message for more information.


Provides warnings and restrictions to prevent a user from exceeding the 2gb storage limit for a Personal Folders .pst file. Can be configured to alert an administrator.

Outlook Recovery

Outlook Recovery locates Outlook files and databases automatically. If you experienced a hard drive failure or deleted an Outlook database by an accident, Outlook Recovery will perform a full scan of that disk in order to locate and undelete/recover the database. If a database is corrupted, Outlook Recovery will repair it so that it can be used with Microsoft Outlook again. Outlook Recovery can recover Outlook databases in PST and OST formats, saving them for using with Outlook or any email application that supports the EML format.


OutlookFix is an Outlook repair software tool for damaged, erased or large Outlook PST files. Restores Outlook files, will undelete emails and files, and lets you reduce the size of Outlook (Outlook 2gb limit fix) solving the common 2Gb size problem.

PST Walker

Outlook .NET pst/ost native parser. Pass the .pst or .ost file by header or extension, strip attachments, get all items (Appointments, Calendar, Folders, Email, Tasks, etc.), recover deleted or orphaned items. Allows you to continue processing if file is corrupt. Works with 97 - 2007 format, all encryption methods, and password protected files. Outlook is not required. Does not use MAPI or CDO. Version 4.20

PSTViewer Pro

Use PstViewer Pro to view, search, print, reply to, and export email stored in your Outlook .PST files. Just start PstViewer Pro and select the folder with your .pst files. Click on the .PST file to reveal folders, emails, and file attachments. Renders Outlook emails in their original html, rich text or text formatting. Export your emails to different formats, including PDF, HTML, MHT, CSV, JPG and more. Can also open .eml and .msg files, Outlook not required.

Recovery for Outlook

Recovery for Outlook repairs corrupted Outlook mailboxes (.pst). The program also supports Exchange Offline Storage Files (.ost). Supported Outlook versions: 2007, 2003, 2002, 2000, 98 and 97

Recovery Toolbox for Outlook

Recover data from Outlook pst files. Recover Exchange ost files and/or convert them into Microsoft Outlook pst files. Export data from pst files into eml and vcf files.

Recoveryfix for Outlook PST Repair

RecoveryFix for Outlook is PST repair software that repairs the corrupt, damaged and inaccessible PST files and restores them to new PST, EML or MSG file formats in a single go. The tool comes integrated with smart and enhanced repairing features that rigorously scan, repair and restore the complete Outlook data files within a matter of minutes. Its advanced algorithms and interactive GUI makes this tool an ideal Outlook PST repair utility for non-technical users to perform complex recovery process with utmost convenience.

Stellar Outlook Manager

With Stellar Outlook Manager you can back-up your important emails, compact large PST file, identify and remove duplicate emails, get back lost password, repair corrupt PST files and even split large PST files. All these functions can be managed conveniently in just a few clicks through a central console.

Stellar Phoenix PST File Splitter

PST File Splitter reduces the size of a large PST file by splitting it into small parts and helps in avoiding the PST corruption situations. Stellar Phoenix PST File Splitter splits large PST file on the basis of email Id, date and folder size and keep the original PST file intact. It allows to create batch files for automating splitting process and also provides the log report of every operation. PST file splitter is available with both single user and corporate versions and efficiently works with Outlook 2010, 2007, 2003, 2002 and 2000.


  1. Doris says

    Diane... In April 2012 my harddrive crashed. I use Microsoft Outlook for EVERYTHING and have been backing up my files to an external drive for the past 4 years. Much to my surprise.... I cannot retrieve my .pst files from the backup. I tried the Microsoft fix-it, I have tried each and every file and I have only been able to get a few files. After reading many posts and looking at additional software that "may be able" to fix the issues, I am really at the end of my rope trying to find a solution. What do you suggest. I need my contacts back!!! Help? I have spent hundreds on paid support and still nothing. Where do I turn. I feel as if my information is right in front of me and I can't get to it. Thanks doris

  2. Doris says

    Yes. It claims they are not pst files. I am sick about this. I love MS outlook but I can't continue to put my information at risk if I can't rely on a good back up. Am I doing something wrong?

    • Diane Poremsky says

      It sounds like the backups were bad. Can you copy them to the local drive? How large are they? If they aren't too big to transfer, i can try to repair one and see what happens. I'm not holding out much hope though.

  3. dinjy says

    This is really a very helpful post. with the help of the given guidelines i have become able to repair my large pst files easily.

  4. Latin Music Booking (@LatinMusicBookg) says

    Hi Diane, I am a new Slapstick and I just found this section, hope you do look at past sections, well.... I was an BCM Outlook user since 2000 however my PST file grew way over the limit and then my BCM OL crashed - when I could not recover and found out it was because BCM OL did not support file larger than 2gb, I just had to dumped OL, but I really loved BCM OL and enjoyed using it. I have not used BCM OL since 2002 so my question is. Has MS corrected the large file problem? and if not, what would you do to divide up the retained files (because of my type of work "Live Music Booking Agent" I save everything sent and received and I had many folders within OL because of how I file stuff ie.. Buyer, Agent, Artist, Venue, Recommend-er, Request Bids, Toss, East, West, Media TV, Media Print, Media Radio, etc... and I save the emails with the attachments) so that when the file reach the limits what does one do to continue within that year or years? Please let me know? anyone's opinion is appreciated. PS: I use Gmail now, it kinda works but I'm not happy using it.

    • Diane Poremsky says

      As of Outlook 2003, there is a new pst format that supports large file sizes, up to 1 TB. The default in 2003 is 20 GB, but they've raised it to 50 GB in outlook 2013. A simple registry change will allow it to grow above 50 GB.

      That said, if you receive a lot of larger attachments, I'd archive by year. If the 50 GB can handle a year's worth, every march I'd archive the previous year's messages to a new pst file. If the pst grows faster than that, I'd archive more often or use a utility (or macro) to save attachments to the harddrive.

  5. George says

    Hi Diane,I have a laptop that started crashing on me. When it was up one time i was able to backup my outlook personal folders to a flash drive. Bad thing was that my main two folders were merged together and is now 4.1 GB. When I went to import into new laptop (I'm using office 2007) i get this error message, "The drive that contains your data file is out of disk space. Empty the Deleted Items folder or create space on the drive by removing some of your files. Access is denied. Verify the disk is not full or write-protected and that the file is not being used". And of course i cannot get the old laptop to operate again to export the pst. files again. Is there anything i can do in this situation.

    • Diane Poremsky says

      Is the laptop drive full? Copy the pst file to the hard drive. If the error message is in error - you have mega amount of free space, it's possible the pst file is corrupt.

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