This article was previously published under Q314916
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The Exchange database is designed to rely on and take advantage of block level file access to a locally attached file system. When files are accessed through the network redirector by using file-sharing protocols such as Server Message Block (SMB) or Common Internet File System (CIFS), some native file system features and methods that Exchange uses cannot be supported.
Versions of Exchange that are earlier than Exchange 2000 function as expected in most respects even when data files are accessed through the network redirector, but Exchange 2000 databases do not mount when they are stored on devices that do not appear to the Exchange system as locally attached block level devices.
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
288212 XADM: Exchange Server and Network Attached Storage Devices
The Exchange administrative interfaces that Microsoft supports for setting and changing Exchange database and transaction log file locations are:
Exchange Performance Optimizer (Exchange Server 4.0, Exchange Server 5.0, and Exchange Server 5.5)
The Exchange Server Administrator program (Exchange Server 4.0, Exchange Server 5.0, and Exchange Server 5.5)
Exchange System Manager (Exchange 2000 Server)
If you use one of these administrative interfaces to try to change a database path to a network shared location, you might receive one of the following error messages:
One or more file locations are not valid. Performance Optimizer requires that file locations reside on fixed, local disk drives. [800FF353]
The specified path is not valid or is incomplete or is not local or does not exist. Specify a valid path name.
The specified destination drive is not a fixed drive.
If you force Exchange Server 4.0, Exchange Server 5.0, and Exchange Server 5.5 files to an invalid location by directly editing the registry, the database starts and seems to run normally, but might become vulnerable to corruption if traffic is heavy or the network becomes unreliable.
When Exchange Server data paths are set to invalid locations, the Exchange Performance Optimizer displays the following error message:
An absent, corrupted, or invalid registry entry was encountered. Reinstall Microsoft Exchange Server. [800FF324]
To resolve this issue without re-installing Exchange Server, use the Exchange Server Administrator program to redirect the database paths to valid locations. You may have to manually copy database and transaction log files to the new locations after you make this change.
In Exchange 2000, database paths are not stored in the registry, but in Active Directory. If you force Exchange 2000 data paths to a network location, the database cannot mount and the following error messages might be logged in the server's Application event log during database startup:
Event Type: Error Event Source: MSExchangeIS Event Category: General Event ID: 9518 Date: 2/12/2001 Time: 1:14:22 PM User: N/A Computer: SERVER1 Description: Error Current log file missing starting Storage Group /DC=COM/DC=COMPANY/CN=CONFIGURATION/CN=SERVICES/CN=MICROSOFT EXCHANGE/CN=MICROSOFT/CN=ADMINISTRATIVE GROUPS/CN=FIRST ADMINISTRATIVE GROUP/CN=SERVERS/CN=SERVER1/CN=INFORMATION STORE/CN=FIRST STORAGE GROUP on the Microsoft Exchange Information Store.