XCLN: OST and PST Quick Reference

• Microsoft Exchange Windows 3.x client, versions 4.0 and 5.0
• Microsoft Exchange Windows 95 client, versions 4.0 and 5.0
• Microsoft Exchange Windows NT client, versions 4.0 and 5.0

SUMMARY

This article provides a quick reference for troubleshooting Microsoft Exchange client offline folders (.ost files).

MORE INFORMATION

Definitions

OST - Offline Folder Storage - A file that contains a local replica of a user's Microsoft Exchange Server-based folders (private and public) and forms. The OST is synchronized with the Microsoft Exchange Server copy for use while working offline. An OST is specific to a particular mailbox and cannot be accessed by other users of Microsoft Exchange Server.

PST - Personal Folder Storage - A file that may contain folders, messages, forms, files and other items. You can create any number of PSTs for use with a single profile. You can also designate a PST as the delivery location for incoming mail.

New Client Installation - If you are installing the Microsoft Exchange client for the first time, during the profile creation you will be asked if you travel with the computer. If you answer yes, an Offline Store provider is set up for you and a file, Exchange.ost, is created. The OST is where the offline folders will be stored.

Existing Client Installation - If this is an existing installation of the Microsoft Exchange client, you can create an offline store using the Offline Folder File Setting button in the Advanced tab of the Microsoft Exchange Server driver property page. If multiple users will be using a single computer, each user needs his or her own OST file.

Creating an OST

How to make a server-based folder available for offline use:

   1. Open the folder property sheet by selecting the folder and clicking
      Properties on the File menu.

   2. Click the Synchronization tab and select Available Offline or Online.

How to disable an OST:

   1. Open the Mail Control Panel.

   2. Select the Microsoft Exchange Server service and click Properties.

   3. Click the Advanced tab, and then click Offline Folder Settings.

   4. Click Disable Offline Use. You may also want to rename the OST file
      on the local computer.

   1. Open the Mail Control Panel.

   2. Select the Microsoft Exchange Server service and click Properties.

   3. Click the Advanced tab, and then click Offline Folder Settings.

   4. Click Compact Now.

   1. Open the Mail Control Panel.

   2. Select the Personal Folders service and click the Properties button.

   3. Click the Compact Now button.

An OST is the preferred method for offline storage, because it allows you to use public folders and organizational forms while working offline. Because an OST acts as a copy of Microsoft Exchange Server-based folders, the data is backed up during the standard Microsoft Exchange Server backup procedures. A local PST must be backed up by the individual owner. One advantage a PST has is the ability to use the remote e-mail features of the Microsoft Exchange client, download headers, move or copy messages, delete unwanted messages before downloading, and read new messages while others are downloading. When using an OST, the synchronization process is not multi-threaded.

OST Sync Log:

During the OST synchronization process, a log file is kept, and it will be placed in the Deleted Items folder at the completion of synchronization. This log file is very useful in determining synchronization details and errors. The following are some of the errors and possible causes:

8004010f - This error may be caused by any of the following reasons:

• You have changed the language of the Organization Forms registry after the OST was created.
• You have two Microsoft Exchange Server sites, where the first has an Organization Forms registry and the second does not. Unless public folder affinity is set correctly, users in the second site will not be able to open the Organization Forms registry and will receive this error.
• You added an Organization Forms registry, but it was later removed.

80040115 - A network error prevented successful completion of the operation. Complete some basic remote procedure call (RPC) network troubleshooting.

User's mailbox deleted from Microsoft Exchange Server:

Because an OST is stamped with a mailbox's unique ID, if a user's mailbox is deleted and re-created on the computer running Microsoft Exchange Server, the OST file will not synchronize with the new mailbox. The only way to recover the data in the OST is to use the following steps exactly before starting the client online:

   1. Start the Microsoft Exchange client in offline mode, using the same
      profile that was used before with the OST.

   2. Add a PST to the profile.

   3. Copy the messages to the PST.

   4. Create a new profile that connects to the new mailbox.

   5. Move the messages from the PST to the new mailbox.