Resolve problems that are caused by duplicate free/busy folders and Offline Address Book folders on an Exchange Server 5.5 site (326637)

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The first server that is installed on an Exchange site becomes the default site folder server. When an Exchange site is created, a site folder GUID is generated. The GUID is a 16-byte sequence of hexadecimal characters. GUIDs are generated by an algorithm that makes it very unlikely that any other Exchange site will have the same GUID. A site folder GUID attribute is stamped on the Information Store Site Configuration object during installation, and this GUID is used by the site folder server to generate and to manage the site folders.

You can view the site folder server and the site folder attributes when you start the Exchange Administrator program in raw mode. To do this, follow these steps. Warning If you use the raw mode of the Exchange Server Administrator program (admin /r) incorrectly, serious problems may occur that may require you to reinstall Microsoft Windows NT Server, Microsoft Exchange Server, or both. Microsoft cannot guarantee that problems that result from using raw mode incorrectly can be solved. Use raw mode at your own risk.

1. Start the Microsoft Exchange Administrator program in raw mode. To do this, type c:\exchsrvr\bin\admin /r at a command prompt.
2. Expand the Site container, and then expand the Configuration container.
3. Click the Information Store Site Configuration object.
4. On the File menu, click Raw Properties to view the site folder server and the site folder GUID attributes.

You can change both the site folder GUID and the site folder server. However, if you change the site folder GUID, all existing free/busy information and all offline Address Book information for your site is destroyed. Additionally, all replicas of the site folders for this site that are on all servers in your Exchange organization are destroyed. The clients must upload all free/busy information before it is accurate again, and the offline Address Books must all be regenerated before the clients can download the information.

If you change the site folder server, the new server performs the site folder checks. The site folder server performs a site folder check one time every 24 hours and one time when the Exchange Server Information Store service is started.

As a best practice, the site folder server should have replicas of the Offline Address Book folders and of the free/busy folder. If replicas of the site folders exist on the site folder server, it is unlikely that a site check will fail because folder replicas are temporarily unavailable.

The directory names of site folders are generated from the site folder GUID by using a specific algorithm. Therefore, the site folder server can read the site folder GUID and calculate what the site folder names should be. The site folder server tries to destroy site folder replicas that do not match the site folder GUID. If no site folders match the site folder GUID, the site folder server creates new site folders.

Some of the folders in the System Folders tree are not site folders. Only the free/busy folder and the Offline Address Book folders are affected by changes to the site folder GUID. If you change the site folder GUID, the Organizational Forms system folder, the EventConfig_SERVERNAME folder, and other system folders are not affected.

How duplicate site folders may be created

Duplicate site folders may be created in either of the following ways:

• The site folder GUID is changed. The site folder GUID can be deliberately changed when an administrator sets a different GUID. The site folder GUID can also be unintentionally changed during the installation of a server that is intended for recovery purposes or for "forklift" purposes.
• A public folder store that includes different site folders is restored on the site.

Each object in an Exchange directory has an Object-Version attribute. When the object is changed in some way (for example, you add a telephone number entry to a mailbox), the Object-Version attribute is incremented by 1. Over time, most objects in an Exchange system have Object-Version attributes whose values are considerably greater than 1. Generally, newer Exchange systems have lower Object-Version attribute values.

When a change to an object is replicated to a server, the Object-Version attribute in the change is compared to the Object-Version attribute that is already on the server. Unless the new Object-Version attribute is greater than or equal to the value that is already on the server, the change is discarded. When the values of the Object-Version attributes are equal, other attributes, such as time stamps, are used to determine if the change is discarded.

The Information Store Site Configuration object frequently has a low Object-Version attribute value, even on sites that have been active for a long time. Few configuration settings are frequently updated on the Information Store Site Configuration object. Other objects that are likely to have low Object-Version attribute values in an Exchange system have generic properties. However, the Information Store Site Configuration object is customized with the site folder GUID and the site folder server attributes when it is created.

You can prevent the site folder GUID for the Information Store Site Configuration object from being unintentionally overwritten by incrementing the Object-Version attribute of the Information Store Site Configuration object. To do this, follow these steps:

1. Create a text file named Import.ini that includes the following information (where Exchange Server computer is the name of the Exchange Server computer and Exchange site name is the name of the Exchange Server site):

   [Import]
   DirectoryService=<Exchange Server name>
   Basepoint=/o=ML/ou=<Exchange site name>
   Container=Configuration
   OverwriteProperties=Yes
   RawMode=Yes
   

2. Create a text file named Import.csv that includes the following three lines (where Exchange site name is the name of the Exchange Server site):

   Obj-Class,Obj-Dist-Name,Directory Name,Admin Note
   Information-Store-Cfg,/o=ML/ou=<Exchange site name>/cn=Configuration/cn=Site-MDB-Config,Site-MDB-Config,an admin note
   Information-Store-Cfg,/o=ML/ou=<Exchange site name>/cn=Configuration/cn=Site-MDB-Config,Site-MDB-Config,~DEL
   

   Note Repeat the last two lines in the Import.csv file as many times as you have to repeat it (several thousand times is sufficient). These two lines create and then remove an Admin note attribute on the Information Store Site Configuration object. Every time these two lines run, the Object-Version attribute increases by 2.
3. In the Exchange Administrator program, import the Admin.exe file and the Import.csv file to each site. To do this, follow these steps:
   1. From the Exchsrvr\Bin subdirectory, run the following command at a command prompt, and then save the changes:

      ADMIN.EXE /I IMPORT.CSV

   2. Run the following command at a command prompt:

      ADMIN.EXE /O IMPORT.INI

How to destroy and regenerate site folders

Important Do not regenerate site folders unless you have exhausted all recovery methods for the replicas of the site folders or unless you specifically want to destroy the contents of the existing site folders.

When an Exchange site is created, a site folder GUID is generated. The site folder GUID is used to name and to identify the Offline Address Book folders and the free/busy folder. When a site folder check is performed, the site folders that are based on the incorrect site folder GUID are destroyed.

In Exchange Server 5.5, a subfolder of the Offline Address Book folder named OAB Version 2 exists. This folder contains the Exchange Server 5.5 version of the offline Address Book. The original Offline Address Book folder is only used in Exchange Server 5.5 for backward compatibility with servers that are running earlier versions of Exchange Server. The OAB Version 2 folder's name is not based on the site folder GUID. The site folder check cannot remove duplicate folders or OAB Version 2 folders that are not valid. However, because the OAB Version 2 folder is a child of the original Offline Address Book folder, copies of the OAB Version 2 folder that are not valid can be destroyed when the site folders are regenerated.

If you have problems with duplicate site folders, and the site folder check has not been able to resolve the problems, you can reset the site folder GUID. Before you reset the site folder GUID, you can follow these steps to make the process faster and more reliable:

1. Replicate the Offline Address Book folder, the OAB Version 2 folder, and the free/busy folders to the site folder server.
2. Remove all replicas of these folders from the other servers in the organization.

If you cannot access the Replicas properties for the folders, use the Instances interface on the Public Information Store objects for each server to make the process faster and more reliable.

Note If you confine all replicas to the site folder server, a site folder check may be successful, and you do not have to reset the site folder GUID.

You can use the Guidgen.exe utility to generate a new site folder GUID. If there are duplicate site folders, clients from some servers may have published their free/busy information to one of the folders, and clients from other servers may have published their information to another folder. In these situations, a temporary loss of some free/busy data may occur when you try to resolve the problem.

Warning If you change the site folder GUID, you must never restore previous backups of any public folder store in the Exchange organization. If you do this, you may cause the following problems:

• Duplicate site folders may be created.
• Existing site folders may be destroyed.
• The site folder server's public database may permanently stop replicating.
• Other public stores on some or all servers may not be able to accept replicas of the site folders.

To resolve these problems, you may have to destroy and then rebuild the public folder stores on some or all servers in the Exchange organization. You cannot reset the GUID for only one site folder. If you reset the GUID, all offline Address Books and free/busy information for the site is deleted.

To reset the site folder GUID and delete all the offline Address Books and the free/busy information in a site, follow these steps:

1. Obtain a copy of the Guidgen.exe utility.
   
   Note If you do not have access to this utility, contact Microsoft Product Support Services. You do not have to run the Guidgen.exe utility on the site folder server or on an Exchange server in your organization. Microsoft PSS can remotely generate and send you a new GUID.
2. Start the Guidgen.exe utility, and then click Registry Format.
3. Click New GUID.
   
   Note the new GUID number that is displayed in the Result box.
4. Start the Microsoft Exchange Administrator program in raw mode. To do this, type c:\exchsrvr\bin\admin /r at a command prompt.
5. Expand the Site container.
6. Expand the Configuration container for the site that you want to rebuild, and then click the Information Store Site Configuration object.
7. On the File menu, click Raw Properties.
8. Scroll through the Object Attributes window, click Site-Folder-GUID, and then click Remove.
9. In the Edit Value box, replace the existing GUID with the GUID that you created in step 3. When you replace the value, you may receive the following error message:
   Some of the characters in the clipboard are not valid for this entry.
   Note Although you receive this error message, the change is made, and the dashes and the braces are removed from the GUID. If you type the GUID, do not type the dashes or the braces.
10. Click Set, and then make sure that the Edit value and the Attribute value are the same.
11. Click Apply, and then click OK.
12. To force an immediate site folder rebuild, stop and then start the Information Store service on the site folder server. If you do not force an immediate rebuild, the folders are rebuilt in the next 24 hours. If there are multiple servers in the site, restart the Information Store services on all the servers in the site. After the site folders have been successfully regenerated by using the Guidgen.exe utility, the only replicas of the site folders are on the site folder server. All the other replicas in the organization are destroyed when the public folder replication is complete.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base: