Norton Antivirus Drivers Hang SMARTDRV.EXE

• Microsoft Windows operating system versions 3.1, 3.11

SUMMARY

Norton Antivirus for Windows and MS-DOS has two drivers that load in the CONFIG.SYS: NAV_.SYS and NAV&.SYS. These drivers can conflict with Microsoft Windows 3.1's SMARTDRV.EXE version 4.0.

MORE INFORMATION

The conflict between the drivers can cause the system to stop responding (hang) during startup or can cause the scanning process to fail. The following are the conditions for conflict.

System Hangs During Boot Process

Both the Norton drivers and SMARTDRV.EXE file automatically load into the UMB area between 640K and 1024K, where they conflict with each other.

There are two solutions to this problem:

1. Modify the AUTOEXEC.BAT file's SMARTDRV.EXE line and add a /L parameter to force SMARTDRV.EXE to load low, as follows

         C:\WINDOWS\SMARTDRV.EXE /L xxxx yyyy
   

   where xxxx is size and yyyy is winsize.

2. Modify the CONFIG.SYS file and add a /B to the NAV&.SYS line:

         DEVICE=C:\NORTON\NAV&.SYS /B
   

Scanning Process Fails

Norton Antivirus may give the following error message on a low-memory machine running SMARTDRV.EXE:

   Not Enough Memory to Scan Application

• Free additional memory by not loading other drivers or terminate-and-stay-resident (TSR) programs.

  -or-

• Disable SMARTDRV.EXE.

NAV_.SYS is used to scan for viruses whenever an application is launched or a file is copied, and detects boot-sector and partition- table viruses. It takes up more memory and is faster than NAV&.SYS.

NAV&.SYS is used to scan when applications are launched and detects boot-sector viruses on floppy drives. It is more compact than NAV_.SYS, and uses overlays. The /B causes NAV&.SYS to use more memory and bypass the conflict in the UMB area.

The Norton products included here are manufactured by a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.