Windows Err Msg: Unable to Enter Protected Mode

 Last reviewed: November 23, 1994
Article ID: Q84422
The information in this article applies to:
  • Microsoft Windows operating system versions 3.1, 3.11

SYMPTOMS

The following error message may appear when you start Microsoft Windows version 3.1 in 386 enhanced mode: 

   Unable to Enter Protected Mode

CAUSE

This message is displayed if 32-bit disk access is enabled and your hard disk controller is not 100-percent compatible with the Western Digital 1003 controller card. If this is the case, the Western Digital driver does not load and the above error message is displayed.

WORKAROUND

To avoid this error message, start Windows 3.1 by typing "WIN /D:F" (without the quotation marks) at the MS-DOS command prompt. This command disables 32-bit disk access for the current Windows session. After Windows has loaded, you can permanently disable 32-bit disk access.

To permanently disable 32-bit disk access, do the following:

  1. Run Control Panel.

  2. Choose the 386 Enhanced icon.

  3. Choose the Virtual Memory button.

  4. Choose the Change button.

  5. Clear the Use 32-Bit Disk Access check box.

KBCategory: kbother kberrmsg
KBSubcategory: winmem win31
Additional reference words: fastdisk 3.10 3.11 WDCTRL fast disk

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Last reviewed: November 23, 1994
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