This article describes how to troubleshoot performance issues in Microsoft Office Outlook 2007

You may experience one or more of the following performance issues in Outlook 2007:

•	Outlook 2007 is slower than earlier versions of Microsoft Office Outlook.
•	Outlook 2007 is slower than expected.
•	Outlook 2007 is slower than expected when you access your mailbox.
•	Outlook 2007 appears to be unresponsive.
•	Outlook 2007 appears to stop responding for a long time.

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The performance issues may be caused by one or more of the following:

•	Minimal computer specifications
•	The latest service pack for Outlook 2007 not installed
•	Large Personal Folders files (.pst) or Offline Folder files (.ost)
•	Outlook .ost files or .pst files that are on a Solid State Drive (SSD)
•	Third-party add-ins
•	Gadgets (This only applies to Windows Vista)
•	Microsoft Office Communicator integration
•	Antivirus software interaction
•	Windows Desktop Search indexing
•	Incomplete closure of .pst files or .ost files
•	POP3 accounts on Windows Vista clients
•	Many Really Simple Syndication (RSS) feeds

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Does the computer meet the system requirements for the 2007 Office suite that you are using?

Make sure that the computer meets the system requirements for the 2007 Microsoft Office suite that you are using. For more information about the system requirements for the 2007 Office system, visit the following Microsoft Web site:If the computer meets only the minimum system requirements, you will not experience optimal performance of the 2007 Office suite.

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Are you running the latest version of Outlook 2007?

We recommend that you run Outlook 2007 Service Pack 1 (SP1). Outlook 2007 SP1 includes the changes from the performance update and from the Business Contact Manager update that is mentioned in this topic.

If you are running the release version of Outlook 2007, we recommend that you install the Outlook 2007 update that is mentioned in the following Microsoft Knowledge Base article, 933493: If Business Contact Manager is installed, you must also install the update that is described in the following in the Microsoft Knowledge Base article, 935569:

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Do you have a large .pst file or a large .ost file?

If you have a large .pst file or a large .ost file, you may experience performance issues during typical operations in Outlook. These typical operations include reading e-mail messages, moving e-mail messages, and deleting e-mail messages.

When you use Outlook 2007 with the Performance Update, or you use Outlook 2007 SP1 or later versions, the following .ost size guidelines generally apply:

•	Up to 2 gigabytes (GB): This size should provide a good user experience on most hardware.
•	Between 2 GB and 4 GB: This size is typically hardware dependent. Therefore, if you have a fast hard disk and much RAM, your experience will be better. However, slower hard drives, such as drives that are typically found on portable computers, experience some application stops when the drives respond.
•	More than 4 GB: This size is where short pauses begin to occur on most hardware.
•	Very large, such as 10 GB or larger: This size increases the frequency of the short pauses, especially while you are downloading new e-mail. You can use Send/Receive groups to manually sync your mail. This synchronization minimizes changes in the local data file during heavy e-mail usage. For more information about how to manage Outlook synchronization, visit the following Microsoft Web sites: http://office.microsoft.com/en-us/outlook/HP052421871033.aspx (http://office.microsoft.com/en-us/outlook/HP052421871033.aspx) http://office.microsoft.com/en-us/outlook/HP030829231033.aspx (http://office.microsoft.com/en-us/outlook/HP030829231033.aspx)

The product team is aware of these issues and is working to improve the performance in future releases of Outlook.

The following blog post describes how to reduce the size of your local data file by using synchronization filters: This is a stop-gap solution and is provided here for reference if you cannot reduce the size of your mailbox. For example, you may be unable to reduce the size of your mailbox if you have to maintain an archive of all e-mail messages, both sent and received, over a time span of several years.

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Are you running a computer that has a Solid State Drive (SSD)?

If you are running Outlook 2007 on a computer that has a solid state drive (SSD), you may experience frequent pauses when you perform typical operations in Outlook. The Outlook product team is aware of this issue and is investigating solutions for a future release.

If your computer is running on a computer that has both an SSD and a non-SSD (rotational) hard disk, you can reduce the frequency of the pauses by moving the .ost file or the .pst files to the non-SSD drive. For more information about how to move your Outlook Data Files, see the following article, "Introduction to Outlook data files," on the Office Online Web site: :

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Do you have many items in a single folder?

If you have a large number of items in any single folder, you may experience performance issues during certain operations in Outlook. The performance issue is especially noticeable when you switch into and out of that folder. Generally, when 10,000 items or more items are in a single folder, these issues can occur.

We recommend that you move several items in these larger folders to separate folders in the same store or to an archive store. For more information, click the following article number to view the article in the Microsoft Knowledge Base: For more information about mailbox size limits, visit the following Microsoft Exchange Team blog entry:

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Do you have any nonessential add-ins or out-of-date add-ins that are installed in Outlook?

If you have nonessential add-ins installed, you may want to remove them from Outlook. To view the add-ins that are installed, follow these steps:

1.	In Outlook, click Trust Center on the Tools menu.
2.	Click Add-ins to display a list of the COM add-ins that are installed.

By default, the following COM add-ins are included in the 2007 Office system:

•	Microsoft Access Outlook Add-in for Data Collection and Publishing
•	Microsoft Exchange Unified Messaging
•	Microsoft Office Groove Proxy for Outlook Add-in
•	Microsoft Office SharePoint Server Colleague Import Add-in
•	Microsoft Office Outlook Mobile Service
•	Microsoft VBA for Outlook Add-in
•	OneNote Notes about Outlook Items
•	Windows Search E-mail Indexer

Any other COM add-ins that are listed in the Trust Center were installed by other software.

Outlook can also use Microsoft Exchange Server client extensions that may cause performance issues. To see the list of currently installed Exchange Server client extensions, click Exchange Client Extensions in the Manage list in the Add-ins section, and then click Go. The Add-In Manager dialog box displays the list of currently installed Exchange Server client extensions.

By default, the following Exchange Server client extensions are included in the 2007 Office system:

•	Delegate Access
•	Deleted Item Recovery
•	Exchange Extensions commands
•	Exchange Extensions property pages

Any other extensions that are listed in the Add-In Manager dialog box were installed by other software.

To determine whether the performance problem is caused by add-ins, run Outlook in safe mode. To do this, press and hold CTRL when you start Outlook. When Outlook starts in safe mode, all COM add-ins and Exchange Server client extensions are disabled.

If the problem goes away when Outlook is running in safe mode, it is likely that one of the add-ins is causing the performance issue. To troubleshoot possible problems that are caused by COM add-ins or Exchange Server client extensions, disable any items that you do not use regularly. Then, restart Outlook. If that does not resolve the problem, disable the remaining add-ins one by one. If that does not resolve the problem, the issue may not be caused by an add-in.

To disable COM add-ins, follow these steps:

1.	On the Tools menu, click Trust Center.
2.	Click Add-ins, click COM Add-ins in the Manage list, and then click Go.
3.	In the COM Add-Ins dialog box, click to clear the check boxes for any COM add-ins that you want to disable.
4.	After you disable the add-ins, click OK, and then restart Outlook.

To disable Exchange Server client extensions, follow these steps:

1.	On the Tools menu, click Trust Center.
2.	Click Add-ins, click Exchange Client Extensions in the Manage list, and then click Go.
3.	In the Add-In Manager dialog box, click to clear the check boxes for any extensions that you want to disable.
4.	After you disable the extensions, click OK, and then restart Outlook.

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Did you install any gadgets that integrate with Outlook?

On a Windows Vista-based computer, remove any gadgets that you downloaded to show your Outlook data. For example, this data may include the Outlook calendar, Outlook tasks, Outlook mail, and Outlook contacts. To remove gadgets on a Windows Vista-based computer, follow these steps:

1.	Click Start, and then click Control Panel.
2.	Click Control Panel Home.
3.	Click Programs.
4.	Click Windows Sidebar Properties.
5.	In the Maintenance section, click View list of running gadgets.
6.	Click any gadget that you want to disable, and then click Remove.

For more information about the Windows Sidebar, view the "How do I customize Windows Sidebar?" Help topic in Windows Vista.

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Is Outlook integration with Communicator enabled?

By default, Outlook includes feature integration with Microsoft Office Communicator. The features that Outlook and Communicator share relate primarily to presence information such as whether someone is busy, away, or in a meeting. To disable feature integration, follow these steps:

1.	In Outlook, click Options on the Tools menu.
2.	Click the Other tab, click to clear the Display online status next to a person name check box under Person Names, and then click OK.
3.	Restart Outlook.

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Is antivirus software running?

If your antivirus software includes integration with Outlook, you may experience performance issues in Outlook. In this case, you can disable all Outlook integration within the antivirus software. Or, you can disable any antivirus software add-ins that are installed in Outlook.

You may have to contact the antivirus manufacturer to determine how to configure the antivirus software to exclude any integration with Outlook or to exclude scanning in Outlook.

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Did you install Windows Desktop Search on a Windows XP-based computer or install Outlook on a Windows Vista-based computer?

Windows Desktop Search (WDS) will index all data in .ost files and in .pst files. However, the indexing of Outlook data occurs only when Outlook is running. Therefore, you may have to leave Outlook running overnight to determine whether the performance issues were related to the building of your search indexes.

Performance issues may increase when Outlook is running in online mode. Such performance issues occur because running Outlook in online mode increases the load on the Exchange Server. This performance issue is especially noticeable when more than one user indexes the Outlook data at the same time by using Windows Desktop Search.

To determine the indexing status for Outlook data, follow these steps:

1.	In Outlook, point to Instant Search on the Tools menu, and then click Indexing Status.
2.	In the Microsoft Office Outlook dialog box, view the number of items that remain to be indexed.

The built-in back-off mechanisms in the indexing component of Windows Desktop Search pause the indexing of Outlook data when the system is under heavy use. The easiest way to let the indexing finish is to leave Outlook running overnight.

Additionally, performance issues are reduced when you run Outlook in Cached Exchange Mode. In this mode, Windows Desktop Search searches the local copy of the mailbox instead of the mailbox content that is located on the server.

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Did the .pst file or the .ost file shut down incorrectly?

If the .pst file or the .ost file shuts down incorrectly, you may receive one of the following error messages the next time that you start Outlook:

•	Error message 1 Outlook cannot open the data file filename until it has been checked for problems.
•	Error message 2 Microsoft Office Outlook’ exited without properly closing your Outlook data file ‘drive:\Users\username\AppData\Local\Microsoft\Outlook\outlook.ost’. ‘Microsoft Office Outlook’ must be restarted. If this error message recurs, contact support for ‘Microsoft Office Outlook’ for assistance.
•	Error message 3 The data file filename was not closed properly’. This file is being checked for problems.

If you receive one or more of these error messages, you may experience performance issues until Outlook finishes the reconciliation process for the .ost file or for the .pst file. The following gear icon is displayed in the status bar while Outlook checks the data file in the background: When this icon disappears, the .pst file or the .ost file is reconciled. If you exit Outlook while the gear icon is present, reconciliation must restart the next time that you run Outlook. We recommend that you leave Outlook running until the gear icon disappears before you exit Outlook.

An incorrectly shut down .ost file or .pst file may occur for one of the following reasons:

•	Antivirus scanning of the file
•	Forced Microsoft Windows shutdown before the Outlook.exe process shuts down completely
•	Outlook add-ins

If you see this issue frequently, and you have to exit Outlook shortly before you shut down your computer, it may be better to shut down Windows while Outlook is still running. We recommend that you do this instead of exiting Outlook and then shutting down Windows shortly after that.

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Do you use a rule that moves items out of the default store?

Rules that move items from your default store into another store can cause performance issues when Outlook downloads e-mail messages. Such performance issues are especially prevalent if you are not running Outlook with the SP1 update.

If you are using rules to move mail from a POP3 account to another store, you can use new functionality in Outlook 2007 that lets you change the delivery location of the POP3 account. In this case, you do not have to use rules to deliver the mail from that account to the separate store.

To do this, follow these steps:

1.	On the Tools menu, click Accounts, and then select the POP3 account in the list.
2.	Click Change Folder at the bottom of the dialog box to select a folder in the separate store to which you want to deliver that account.

If you do not use a POP3 account, you can also work around this issue by setting your target folder for all rules to be in the same Outlook store. Then, use the AutoArchive feature to move messages out of the default store in bulk. For more information about how to configure the AutoArchive feature, click the following article number to view the article in the Microsoft Knowledge Base:

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Are you connected to a POP3 server?

For more information about a possible workaround if you are connected to a POP3 server and your download speeds are very slow, click the following article number to view the article in the Microsoft Knowledge Base:

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Are you synchronizing many RSS feeds?

If you are synchronizing many RSS feeds into Outlook, you may experience performance issues with certain ordinary operations. By default, all RSS feeds are synchronized automatically at set intervals. If you have too many feeds, Outlook may become unresponsive.

You can create a separate Send/Receive group that contains only your RSS feeds, and you can remove them from the group your default mail account is in. This will enable you to sync the RSS feeds on-demand instead of at set intervals.

For more information about how to manage Send/Receive groups, see the articles on the following Office Online Web site: Thank you! Your feedback is used to help us improve our support content. For more assistance options, visit the Help and Support Page (http://support.microsoft.com/).

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