MS-DOS Error Msg: Unable to Control A20 Line (73713)
The information in this article applies to:
• Microsoft MS-DOS operating system
• Microsoft Windows 95
• Microsoft Windows 98
• Microsoft Windows Millennium Edition
This article was previously published under Q73713
SUMMARY
The following error message is generated when the device driver
HIMEM.SYS is being loaded and doesn't have a machine handler chosen:
ERROR: Unable to control A20 Line
There are two workarounds for this problem:
• Add the "/M:x" switch to the HIMEM.SYS line in the CONFIG.SYS file,
where x is number from the valid range of 1-14 and 16, shut down and
then restart your computer. For example:
DEVICE=C:\DOS\HIMEM.SYS /M:1
NOTE: In Windows 95/98, The Himem.sys file is located in the Windows
folder, not the DOS folder.
NOTE: An incorrect handler may lock or hang the system at boot up.
You should have an MS-DOS version 5.0 bootable floppy disk
available to boot from before you experiment with different machine
switches.
• Upgrade your machine's BIOS or contact your machine vendor for
assistance in modifying your CMOS settings. You may need to disable a
FastGate (or similar) option.
For more information, query on the following words in the Microsoft
Knowledge Base:
Modification Type: |
Major |
Last Reviewed: |
5/10/2003 |
Keywords: |
kbenv kberrmsg kbinfo KB73713 |
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