How to troubleshoot synchronization problems when you synchronize your Exchange Server mailbox with your .ost file in Outlook

This following information describes how to troubleshoot problems that you may experience when you synchronize an Exchange Server mailbox with an .ost file.

Determine whether the offline folders are being synchronized

To determine whether the offline folders are synchronizing correctly, follow these steps:

1. Right-click the folder that you want to verify, and then click Properties.
2. Click the Synchronization tab. If you do not see the Synchronization tab, you did not set up your profile to use offline folders.
3. Under Statistics for this folder, verify the settings in the following fields:
   
   Last Synchronized on: Date
   
   Server folder contains:# Items
   
   Offline folder contains:# Items

If synchronization is working correctly, the number of items in the Server folder contains field and in the Offline folder contains field are the same. If synchronization is not working correctly, or if synchronization does not work correctly between the server folder and the offline folder, you must verify the profile settings. To do this, follow these steps, as appropriate for the version of Outlook that you are running.

Outlook 2003

1. On the Tools menu, click E-mail Accounts.
2. In the E-mail Accounts dialog box, make sure that the View or change existing e-mail accounts option is selected under the E-mail section, and then click Next.
3. In the Deliver new mail to the following location list, make sure that Mailbox - account name is selected.
4. Click the Microsoft Exchange Server object, and then click Change.
5. Confirm that the Use Cached Exchange Mode option is selected, and then click Next.
6. Click Finish, and then click OK.
7. Exit Outlook, and then reopen Outlook

Outlook 2007

1. On the Tools menu, click Account Settings.
2. Click the Data Files tab, and then make sure that Mailbox - account name is set as the default.
3. Click the E-mail tab.
4. Click Mailbox - account name, and then click Settings.
5. Click the Advanced tab, verify that the Use Cached Exchange Mode option is selected, and then click OK.
6. In the Account Settings dialog box, click Close.
7. Exit Outlook, and then reopen Outlook

Synchronize the folders again

After you check these settings, use one of the following methods to synchronize the folders again.

Manual synchronization

1. In the Folder List pane, click the folder that you want to synchronize.
   If you do not see the Folder List pane, click Folder List on the Go menu.
2. On the Tools menu, point to Send/Receive, and then click This Folder (Microsoft Exchange Server) to synchronize one offline folder, or click Send/Receive All to synchronize all offline folders.

When the synchronization procedure starts, you see a synchronization status message in the lower-right part of the screen. If you have many items in the mailbox and you have not synchronized the offline folders for a while, the synchronization procedure may take more than 30 minutes.

Automatic synchronization

To synchronize all offline folders automatically every time that you are online and every time that you exit Outlook, follow these steps:

1. On the Tools menu, click Options.
2. Click the Mail Setup tab.
3. In the Send/Receive section, click to select the Send immediately when connected check box.
4. Click Send/Receive.
5. In the Send/Receive Groups dialog box, make sure that the Perform an automatic send/receive when exiting option is selected, and then click Close.
6. Click OK.

Create a new .ost file and synchronize the offline folders again

If all folders except the Inbox folder are synchronized, or if you cannot synchronize the folders, you may have a damaged .ost file. To resolve this issue, create a new .ost file and then synchronize the folders again.

How to create a new .ost file and synchronize the folders

To create a new .ost file, rename the old .ost file, and then synchronize the new .ost file with the computer that is running Microsoft Exchange Server. When you rename the old .ost file, Outlook creates a new file. To do this, follow these steps:

1. Exit all programs.
2. Click Start, point to Search, and then click For Files or Folders.
3. In the search dialog box, click All files and folders.
4. In the All or part of the file name tab, type *.ost .
5. Do not type anything in the A word or phrase in the file box.
6. Click the hard disk in the Look in list. Then, under the More advanced options option, click to select the Include subfolders check box, and then click Search
   
   In the Name column, you see the .ost file. The default location for the .ost file is as follows.
   
   For Microsoft Windows 2000, Microsoft Windows NT, Microsoft Windows XP and Microsoft Windows Server 2003
   C:\Documents and Settings\user name\Local Settings\Application Data\Microsoft\Outlook
7. Right-click the .ost file, and then click Rename. Rename the file by using a different file name extension, such as an .old file name extension instead of the .ost file name extension.
8. On the File menu, click Close.
9. Start Outlook, point to Send/receive on the Tools menu, and then click Send/Receive All.

You see the status of the new synchronization in the lower-right part of the screen, and you now have a new .ost file.

Because the .ost file is a replication of the information that is stored in the Exchange Server mailbox, this procedure does not damage any information.

Replace damaged Exchange Server support files

If you are still not able to restore synchronization, the Microsoft Exchange Server service support files may be damaged. To replace damaged Exchange Server support files, you must first remove the Exchange Server service support files and then replace the deleted files with the original Outlook files.

How to remove the Microsoft Exchange Server service support files for Outlook 2003

To do this, follow these steps:

1. Click Start, point to Programs, and then click Windows Explorer.
2. Rename the following files by using an .old file name extension:
   • Emsabp32.dll
   • Emsmdb32.dll
   • Emsui32.dll
   Notes
   • To rename the file, right-click the file, and then click Rename.
   • The default location for this file is as follows:
     C:\Program Files\Common Files\System\MSMAPI\1033

How to remove the Microsoft Exchange Server service support files for Outlook 2007

To do this, follow these steps:

1. Click Start, point to Programs, and then click Windows Explorer.
2. Rename the following file by using an .old file name extension:
   Emsmdb32.dll
   Notes
   • To rename the file, right-click the file, and then click Rename.
   • The default location for this file is as follows:
     C:\Program Files\Microsoft Office\OFFICE12

How to replace the Exchange Server service support files

To replace the support files that you renamed from the original media, follow these steps:

1. Click Start, click Run, type control, and then click OK.
2. Double-click Add/Remove Programs.
3. Click Microsoft Office, and then click Change.
4. Click Reinstall or Repair, and then click Reinstall Office.

For more information about offline folders and the synchronization procedure, click the following article number to view the article in the Microsoft Knowledge Base: