Windows Err Msg: Attempt to Load Duplicate...(PC Tools/Norton) (79527)

SYMPTOMS

The following message may appear when you attempt to start Windows in enhanced mode:

Attempt to load duplicate device file that may be needed to run Windows in 386 enhanced mode; run Setup again.

c:\windows\system\vdmadx.386

CAUSE

This error is due to a conflict between PC Tools (versions 7.0 and later) and Norton Desktop for Windows (version 1.0), both of which are adding their own virtual device drivers (VxDs) to the [386Enh] section of the SYSTEM.INI file.

PC Tools installs:

   DEVICE=VDMAD.386   (Virtual DMA-REPLACES "device=*vdmad")
   DEVICE=VFD.386     (Virtual Floppy Disk-REPLACES "device=*vfd")

Norton Desktop for Windows installs:

   DEVICE=VFINTD.386  (Virtual Floppy Interrupt)
   DEVICE=VDMADX.386  (Virtual DMA-REPLACES "device=*vdmad")
   DEVICE=VNSS.386    (Virtual Screen Saver)

The PC Tools VDMAD.386 file and the Norton VDMADX.386 file BOTH replace the Windows internal device *vdmad. PC Tools installs VDMAD.386 at the beginning of the [386Enh] section, and Norton Desktop installs VDMADX.386 at the end of the [386Enh] section. When Windows is loading, it loads the PC Tools device driver first and then tries to load the duplicate driver VDMADX.386, which produces the error message.

WORKAROUND

Remark the Norton Desktop DEVICE=VDMADX.386 line in the [386Enh] section of SYSTEM.INI. Remarking both device lines will cause Windows to exit to the MS-DOS command line when Windows tries to load in enhanced mode. If you need to remark both lines, place the line

device=*vdmad

in the [386Enh] section of SYSTEM.INI.

MORE INFORMATION

Symantec has confirmed that this problem only occurs when PC Tools is installed after Norton Desktop. Norton Desktop detects the PC Tools DMA device driver and uses it; whereas, PC Tools does not detect the Norton Desktop DMA device driver. According to Symantec, Norton Desktop for Windows functions correctly with the PC Tools VDMAD.386 device driver.

For more information on these device drivers, query on the following words:

windows and 3.00 and device=*vdmad

The Norton Desktop and PC Tools products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.