Dynamic Disks Are Offline If Controller Driver Is Not Started at Boot

If the driver for the second mass storage controller is not set to start at boot, the devices connected to that controller may not be available for use after Windows 2000 has started. The disks may appear in the Disk Management snap-in as "Offline." This is especially true if the disks are dynamic disks.

The default for all mass storage device drivers is to be set to start at boot. This setting is not changed by Windows, but may have been manually changed by a user to start at "System" time.

The disks appear as Offline because the dynamic disk drivers have already started and checked for any dynamic disks to make available. If the driver for the controller for the dynamic disks has not yet started, the dynamic disks are not made available.

To make a disk online and available, right-click the disk in Disk Management, and then click Reactivate Disk. For a volume that spans more than one disk, it may be sufficient to click only one of the disks.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

You can also make the disks available by changing the Start value in the registry for the controller with the dynamic disks to a value of 0x0 (boot). For additional information, click the article number below to view the article in the Microsoft Knowledge Base: