Rescuing ANSI PSTs that are stuck at 2GB

This page discusses the problem of PSTs made by older versions of Outlook that have grown to 2GB in size and which Outlook will no longer open. In some but not all cases, our product Upstart can rescue such PSTs. If you arrived at this page from outside our Web site you might like to go to the product’s home page to get an idea of what it’s all about.

The Problem

Early versions of Microsoft Outlook (2007, 2000 and 2002) worked with one kind of PST, called an ANSI PST, that was limited in size to 2 gigabytes. Outlook 2003 introduced a new type of PST, called a Unicode PST, that was better in many ways especially in that they could grow to much larger sizes, in fact up to 50GB. Outlook 2003 and all later versions support both kinds but create Unicode PSTs by default.

Many people who started using Outlook in the early days kept on using their ANSI PSTs even after upgrading to Outlook 2003 and later. And many of these PSTs grew to that maximum 2GB size. Which created a horrible problem because Outlook was somehow able to allow these PSTs to grow to a size larger than it could open! So, if a PST went over the limit in one session, Outlook would not be able to open it in the next. And there was no recourse.

Is there a Solution?

We know of no guaranteed solution to this "stuck PST" problem. Our product, Upstart, which is a tool for PST management can however help in certain cases. The way it rescues a stuck PST is to copy its contents into a new Unicode PST. The only way to be sure if Upstart can successfully rescue any particular PST is to try it and see. There are several reasons why the process can fail, including the fact that over-sized PSTs often become corrupted as well. To enable you to determine if Upstart will work for any particular case, we offer a free test version described in the next section.

Upstart's ANSI PST Tester

To find out if Upstart can save an over-sized ANSI PST, please download our test program which is a stripped-down version of the product. Use it to find the PST in question, then click its "Try to open PST" button. If the program tells you that it can successfully open the PST then you can trust that the full version of Upstart will be able to convert it to a Unicode PST for you. And, if it tells you that it cannot then, sorry, but Upstart will not be able to help. (Success opening a PST with the Tester does not guarantee that every item in the PST can be rescued; a PST can be damaged in ways other than being too big for Outlook to open and, when this occurs, some data may not be retrievable.)

How to run the Tester

The Tester needs to run on a Windows system with Outlook 2003, the 32-bit edition of Outlook 2007 or the 32-bit edition of Outlook 2010 installed. The later the version of Outlook, the better chance there is that the test will succeed. (We have versions of Upstart that work with 64-bit editions of Outlook but the Tester is currently available only in a 32-bit edition.)

Download the Tester

The Tester is provided as an executable program in a ZIP file. Please click one of these two links to download it:

Tester for 32-bit editions of Outlook.

Tester for 64-bit editions of Outlook.