Microsoft has imposed a 2GB file size limit on PST and OST, so that they don’t increase beyond a point. When a file crosses the limit, it becomes damaged and is unable to open on Outlook. Lets look at some steps to configure the file size limit on PST file.
In Outlook 2003 and Outlook 2010 email management clients, PST files are formatted using the American National Standards Institute (ANSI) and UNICODE format. Now, these file formats come with a size limitation of 2GB, which is controlled by two registries, namely, The MaxFileSize registry entry and The WarnFileSize registry entry. The MaxFileSize registry determines the maximum file size till which a PST file or an Outlook file can expand to. This registry allows Outlook to prevent the file from growing beyond this point. Meanwhile, the WarnFileSize registry determines the limit till which data can be added to a PST and stops the file from storing any more data, thereby protecting it from getting corrupted. If that happens, then users are prompted to recover PST file. Before going forward, users are advised that the steps mentioned below involve you making changes to the registries in order to set a limit to the PST file. Dabbling in registries has its own risk as if it is done incorrectly, it might cause problems in Outlook. Users are also advised to make a back-up for the registry so that they can restore it if a problem occurs. Now, in order to start editing the registries, close the Outlook application and click on ‘Start’. Then, access the ‘Run’ function and type ‘regedit’ and click on ‘OK’. When the window opens, expand ‘My Computer’ which is located in the left pane and then expand ‘HKEY_CURRENT_USER’. After that expand Software, and then expand Policies. Under the ‘Policies’ header, expand ‘Microsoft’ and then expand ‘Office’. Now, if you are using Outlook 2003, then expand 11.0, if you are using Outlook 2007, then expand 12.0 or if Outlook 2010 is being used by you, then expand 14.0. After selecting the appropriate version, then expand ‘Outlook’. To continue with the recover PST process, click on ‘PST’ and then right-click on the ‘MaxFileSize’ in the right window pane. Select the ‘Modify’ option and type the memory limit in the Value data box. Then click on ‘OK’. Remember, you would have to click on the ‘Modify’ option and enter the file limit value individually for WarnFileSize, MaxLargeFileSize and WarnLargeFileSize registries. However, if the registries do not exist, you would first have to create them in order to accomplish the above mentioned steps. Open the Regedit window and expand the following, for Outlook 2010, expand ‘HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook’, for Outlook 2007, expand ‘HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Outlook’ and for Outlook 2003, expand ‘HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\11.0\Outlook’. On the ‘Edit’ menu, go to ‘New’ and select ‘Key’. After that, type ‘PST’ and press ‘Enter’. Again go to the ‘Edit’ menu, go to ‘New’ and select DWORD. The, type the name of the registry, that is ‘MaxFileSize’. In order to create rest of the registries, follow the above steps that tell you how to create a key and a DWORD. If even the PST file gets corrupted after the breaking the 2GB file size barrier, you can use the DataNumen Outlook Repair tool from DataNumen to recover PST.