This article was previously published under Q191579
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When you view My Computer or Windows Explorer, some or all of your drivesmay be missing. When you view Device Manager, the missing drives may bedisplayed, and you may be able to gain access to the drives by clickingStart, clicking Run, typing the drive letter in the Open box, and thenclicking OK. The drives are accessible at a command prompt or in Safemode, and can be access by ScanDisk and Disk Defragmenter.
This behavior can occur if the PowerToys TweakUI tool is installed andconfigured to hide one or more of your drives.
To resolve this behavior, follow these steps:
Click Start, point to Settings, and then click Control Panel.
On the My Computer tab, click to select the check boxes of the drives that are currently hidden.
Click Close, and then restart your computer.
This issue can occur if you install TweakUI in Windows 98, and then upgrade to Windows Millennium. You can also install TweakUI on Windows Millennium.
If the TweakUI tool is not installed, install it from the Windows 98CD-ROM and then follow steps 1-4. For information about how to installthe TweakUI tool, please see the following article in the MicrosoftKnowledge Base:
190643 How to Install and Uninstall the TweakUI Tool in Windows 98
This resolution may also work in Win 2000, if TweakUi was installed prior to upgrading the OS.
The TweakUI tool can also be used to hide mapped network drives.