What is Oversized PST File Problem?

Microsoft Outlook 2002 and earlier versions limit the size of Personal Folders (PST) file to 2GB. Whenever the PST file reaches or exceeds that limit, you will not be able to open or load it any more, or you cannot add any new data to it. This is called oversized PST file problem.

Outlook has no built-in way to rescue the oversized PST file that is inaccessible. However, Microsoft provides an external tool pst2gb as a makeshift, which can restore the file to a usable status. But for some cases, this tool will fail in restoring the oversize files. And even if the restore process succeeds, some data will be truncated and lost permanently.

Microsoft also released several service packs so that when the PST file approaches the 2GB limit, Outlook cannot add any new data to it. This mechanism, to a certain extent, can prevent the PST file from being oversized. But once the limit is reached, you can hardly do any of the operations, such as send/receive emails, make notes, set appointments, etc., unless you remove bulk of data from the PST file and compact it thereafter to reduce its size. This is very inconvenient when Outlook data grow larger and larger.

Since Microsoft Outlook 2003, a new PST file format is used, which supports Unicode and doesn’t have the 2GB size limit any more. Therefore, if you are using Microsoft Outlook 2003 or 2007, and the PST file is created in the new Unicode format, then you don’t need to worry about the oversize problem any more.


1. When you try to load or access an oversized Outlook PST file, you will see error messages, such as:

xxxx.pst can not be accessed – 0x80040116.


Errors have been detected in the file xxxx.pst. Quit all mail-enabled applications, and then use the Inbox Repair Tool.

where ‘xxxx.pst’ is name of the Outlook PST file to be loaded or accessed.

2. When you try to add new messages or items to the PST file, and during the adding process, the PST file reaches or goes beyond 2GB, you will find Outlook just refuses to accept any new data without any complaints, or you will see error messages, such as:

The file could not be added to the folder. The action could not be completed.


Task ‘Microsoft Exchange Server – Receiving’ reported error (0x8004060C): ‘Unknown Error 0x8004060C’


The file xxxx.pst has reached its maximum size. To reduce the amount of data in this file, select some items that you no longer need, then permanently (shift + del) delete them.


Task ‘Microsoft Exchange Server’ reported error (0x00040820):’Errors in background synchronization. In most cases, further information is available in a synchronization log in the Deleted Items folder.’


Can’t copy the item.


As stated above, Microsoft doesn’t have a way that can solve the oversized PST file problem satisfactorily. The best solution is our product DataNumen Outlook Repair. It can recover the oversized PST file without any data losses. To do this, there are two alternative methods:

  1. If you have Outlook 2003 or higher versions installed on your computer, then you can convert the oversized PST file into the new Outlook 2003 unicode format, which doesn’t have the 2GB limit. This is the preferred method.
  2. If you don’t have Outlook 2003 or higher versions, then you can split the oversized PST file into several smaller files. Each file contains a part of the data in the original PST file, but it is less than 2GB and independent from the others so that you can access it separately with Outlook 2002 or lower versions without any problems. This method is a little inconvenient as you need to manage multiple PST files after the split operation.