Microsoft Office Outlook 2007 and Microsoft Office Outlook 2003 have both a different format and a larger overall size limit for the personal folders (.pst) file than the .pst files that are in the earlier versions of Microsoft Outlook. In Outlook 2002 and earlier, the .pst files are in the American National Standards Institute (ANSI) format, and the overall size has a limit of 2 gigabytes (GB).

By default, .pst files are in the Unicode format in Outlook 2007 and in Outlook 2003. Additionally, the overall size of the .pst files has a limit that is more than the 2-GB limit that is imposed by the ANSI .pst files. By default, the limit for a Unicode .pst file in Outlook 2007 and in Outlook 2003 is configured to be 20 GB. For more information, click the following article number to view the article in the Microsoft Knowledge Base: As in earlier versions of Outlook, Outlook 2003 Internet Message Access Protocol Version 4rev1 (IMAP4) accounts and HTTP accounts use .pst files that do not use the Unicode format. Therefore, the .pst files for IMAP or HTTP accounts in Outlook 2003 are limited to 2 GB. In Outlook 2007, the Internet Message Access Protocol Version 4rev1 (IMAP4) accounts and HTTP accounts do use Unicode format .pst files and are not limited to 2 GB.

If you want to access an Outlook 2007 or Outlook 2003 .pst file from a different computer that has an earlier version of Outlook installed, or if you installed Outlook 2007 or Outlook 2003 and have decided to remove it and to use Outlook 2002 or earlier, you must change your .pst file back to an ANSI format. To do so, follow these steps:

1.	Start Outlook 2007 or Outlook 2003.
2.	On the File menu, click Data File Management, and then click Add.
3.	Click Outlook 97-2002 Personal Folders File (PST).
4.	Click OK.
5.	Name the .pst file, or click OK to accept the default name.
6.	Click OK.
7.	Click Close.
8.	Click Folder List at the bottom of the navigation pane.
9.	In the navigation pane, you will now see your new .pst file that you named in step 5.
10.	Drag the .pst file information from your existing Outlook 2007 or Outlook 2003 folders to the new .pst file that you created. Note If you have e-mail messages or other items that contain Unicode characters, they do not appear in the new .pst file that you created.

Microsoft Office Outlook 2007 and Microsoft Office Outlook 2003 supports both American National Standards Institute (ANSI) and UNICODE personal folders (.pst) and offline folder (.ost) files. This article describes how to use the following four registry entries to limit the size of both the .pst and the .ost files:

•	The MaxFileSize registry entry
•	The WarnFileSize registry entry
•	The MaxLargeFileSize registry entry
•	The WarnLargeFileSize registry entry

Note The WarnLargeFileSize and WarnFileSize registry entries do not enable Outlook to warn you before the file size limit is reached.

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The MaxFileSize registry entry

The MaxFileSize registry entry determines the absolute maximum size that both the .pst and the .ost files can grow to. After this maximum size is reached, Outlook does not permit the size of the file to grow beyond this size.

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The WarnFileSize registry entry

The WarnFileSize registry entry determines the maximum data that both the .pst and the .ost files can have. After this maximum data is reached, neither the .pst nor the .ost files are permitted to add any more data. However, the size of the physical file may still increase because of internal processes.

In the following table, the MaxLargeFileSize registry entry and the WarnLargeFileSize registry entry refer to a UNICODE formatted (new Large format) file, and the MaxFileSize registry entry and the WarnFileSize registry entry refer to an ANSI formatted (an earlier Microsoft Outlook format) file. The UNICODE values are set in megabyte (MB) increments, while the ANSI values are set in byte increments.

Name	Type	Valid Data Range	Default
MaxLargeFileSize	REG_DWORD	0x00000001 – 0x00005000	0x00005000 20,480 (20 GB)
WarnLargeFileSize	REG_DWORD	0x00000000 – 0x00005000	0x00004C00 19,456 (19 GB)
MaxFileSize	REG_DWORD	0x001F4400 – 0x7C004400	0x7BB04400 2,075,149,312 (1.933 GB)
WarnFileSize	REG_DWORD	0x00042400 – 0x7C004400	0x74404400 1,950,368,768 (1.816 GB)

The policy location for the registry entries is located in the following path in Registry Editor.

Outlook 2007

The user preference location for the registry entries is located in the following path in Registry Editor:

Outlook 2003

The user preference location for the registry entries is located in the following path in Registry Editor:

When you start Microsoft Outlook or try to open a personal folders (.pst) file or an offline folders (.ost) file, you may receive the following error message: where <file_path> is the path to the .pst file.

If you run the Inbox Repair Tool (Scanpst.exe), the file does not resolve the problem.

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This problem occurs because the .pst and the .ost files have a 2 gigabyte (GB) size limitation, and the error message occurs when it is exceeded. The Inbox Repair Tool cannot correct this problem.

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To resolve this problem, download the tool from the following Microsoft Download Center link: NOTE: Use the tool to create a truncated copy of the .pst file. The copy that is left after the tool completes does not have all the original data because the tool cuts a user defined amount of data from the file.

Recovery Limitations of the 2 GB Truncation Utility:

•	You must have 2 GB of free hard disk space (to make a copy of the .pst file).
•	The utility truncates the .pst file to under 2 GB. To have enough working space, truncate the file between 20 to 25 megabytes (MB) less than the 2 GB limit. The truncated data is removed from the new copy, which means some messages are missing from the recovered copy.

You can use this process to attempt to recover the data, but is not 100 percent successful. If this tool does work, it does not recover all of the data (the truncated data is missing).

Use the following steps to recover the data:

1.	Download the tool from the following Microsoft Download Center link: http://www.microsoft.com/downloads/details.aspx?FamilyID=B33B1DFF-6F50-411D-BBDF-82019DDA602E&displaylang=en (http://www.microsoft.com/downloads/details.aspx?FamilyID=B33B1DFF-6F50-411D-BBDF-82019DDA602E&displaylang=en)
2.	Extract the 2gb152.exe file to an empty folder. You should see the following five files: • Msstdfmt.dll • Msvbvm60.dll • Pst2gb.exe • Readme.rtf • Readme.txt
3.	Start the Pst2gb.exe program.
4.	Click Browse to select the oversized .pst file, and then click Open.
5.	Click Create, select the name and location of the truncated data file that you want to create, and then click Save.
6.	Type in the amount of the data that you want to truncate in the .pst file. There is not a correct amount that you use. You can receive the best results if you use 20 to 25 MB, but you may have to truncate more or less. For example, if you truncate 25 MB of data and the process works, repeat the process and truncate the original oversize .pst file by only 15 MB. If that works, then try the process with 5 MB. If 25 MB does not work, repeat the process and truncate the original .pst by 35 MB. If the process does not work, increase the amount until the process is successful.
7.	Run the Inbox Repair Tool (the Scanpst.exe file) on the smaller .pst file.
8.	Open the repaired .pst file in Outlook.
9.	(This step is recommended but the step is optional) If the file opens, right-click the root folder of the .pst, click Properties, and then click Compact Now to start the compression. For a file of this size, the compression may take approximately 4-8 hours.
10.	If the file does not open, discard the truncated .pst file, and repeat the process with the original .pst file. Truncate more data than in the first attempt, and try the process again.
11.	Install the following update or hotfix depending on the version of Outlook that you have. To do this, view the following article in the Microsoft Knowledge Base: 245025 (http://support.microsoft.com/kb/245025/) How to obtain and install the Office 2000 SR-1/SR-1a Update These updates prevent Outlook from allowing the .pst file to exceed the 2 GB maximum size. Use one of the following methods to manage the size of the .pst files:   • Use more than one .pst file. • Use the archive feature. • Save attachments to a file system folder and delete them from messages.

The English-language version of this tool should have the following file attributes or later:
 

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Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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It is possible that you may receive the following error message when you try to run the 2 GB Truncation Utility: If you receive this error message, use the following steps.

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Microsoft Windows 98, Microsoft Windows 98 SE, Microsoft Windows ME

1.	Copy the MSstdfmt.dll file to the C:\Windows\System folder.
2.	Open a command prompt, and then type the following command: REGSVR32 C:\Windows\System\MSSTDFMT.DLL

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Microsoft Windows NT, Microsoft Windows 2000, and Microsoft Windows XP

1.	Copy the MSstdfmt.dll to the C:\<windir>\System32 folder.
2.	Open a command prompt and type the following command REGSVR32 C:\windir\System32\MSSTDFMT.DLL where windir is either the WINNT or the Windows directory.

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