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Rebuild VMM32.VXD while keeping apps?

Posted on 1998-11-10
Medium Priority
Last Modified: 2013-12-29
Under Win95B (OSR 2), how can we re-create the VMM32.VXD file without having to reinstall all the user applications?  
We fear that just running SETUP without any special tricks will rebuild the VXD but require reinstalling everything.  Is this true?
Question by:paulnic
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Expert Comment

ID: 1727383
PSS ID Number: Q167889
Article last modified on 12-15-1997

The information in this article applies to:
 - Microsoft Windows 95 OEM Service Release version 2.1
When you set up OEM Service Release version 2.1 (OSR2.1) over OEM Service
Release 2 (OSR2) and restart your computer, you may receive an error
message stating that the Vmm32.vxd file is missing or damaged, or you may
not be able to boot Windows.
These errors can occur if either of the following conditions exists:
 - The Vmm32.vxd file was not rebuilt properly or was damaged, resulting
   in an error message stating that "Vmm32.vxd is missing or corrupt."
 - The addition of Universal Serial Bus (USB) support is causing a
   conflict with the system and Windows 95 is unable to boot normally.
To resolve this issue, use the appropriate method:
Vmm32.vxd Missing or Damaged
If you receive an error message stating that the Vmm32.vxd file is missing
or damaged, the rebuilding of the Vmm32.vxd file was unsuccessful,
preventing Windows from booting properly and processing the RunOnce
section of the registry.
You must uninstall OSR2.1 using the OSR2.1 real-mode uninstall tool
(Rem.pss) on the installation disk. To use the uninstall tool, follow
these steps:
1. Restart your computer.
2. Press the F8 key when you see the "Starting Windows 95" message, and
   then choose Safe Mode Command Prompt Only from the Startup menu.
3. Copy the Rem.pss file to the root folder of the boot drive as
   Remusb.bat (do not copy it to Rem.bat; "Rem" is a reserved command
   and it will not function).
4. Type "remusb" (without quotation marks) to restore the original files
   that were renamed with an .o20 extension.
5. To complete the uninstall process, restart your computer and use the
   Add/Remove Programs tool in Control Panel to remove the program
   "WDM/USB Supplement."
   NOTE: This program may not be listed in the Add/Remove Programs tool.
   If it is not listed, skip this step.
6. Delete the Remusb.bat file from the root folder of the boot drive.
NOTE: The Rem.pss file has only been tested when the first reboot does not
succeed. Failure to boot at any other time may not be resolved by the
Rem.pss file process.
Windows 95 Cannot Boot Because of a Conflict
If Windows 95 cannot boot because of a conflict, use the following steps:
1. Restart your computer.
2. Press the F8 key when you see the "Starting Windows 95" message, and
   then choose Safe Mode from the Startup menu.
3. Rename the Detroit.bat file to Autoexec.bat. The Detroit.bat file is
   your original Autoexec.bat file that was renamed by OSR2.1 Setup.
4. Troubleshoot using standard Safe-mode troubleshooting.
For information about how to troubleshoot Windows using Safe mode, see the
following article in the Microsoft Knowledge Base:
   ARTICLE-ID: Q156126
   TITLE     : Troubleshooting Windows 95 Using Safe Mode
Additional query words: 95
Keywords          : osr2 win95 kbsetup
Version           : 95
Platform          : WINDOWS
Copyright Microsoft Corporation 1997.


Author Comment

ID: 1727384
Thanks for the info.  Unfortunately, we're not working with OSR 2.1, just trying to recover from some damage to files on the hard drive without reinstalling all apps.  Unless I missed it, this article doesn't seem to discuss how to re-create VMM32.VXD without having to reinstall applications.

Expert Comment

ID: 1727385
The problem might not be the VMM32.VXD but some other device driver or harware problem causing win95 to display a VMM32 error.

One of the best examples is a UMAX scanner connected to a 350Mhz and above computer. (Umax has a patch for that).

Let me know your hardware configuration , and what was the latest software/driver you installed ?

try To extract the VMM32.VXD using the extract command at the dos prompt where the win95 cabs are.

EXTRACT vmm32.vx* /A

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Expert Comment

ID: 1727386
There seems to me some misconseption you have been given. VMM32.VXD is the virtual device manager that dynamically loads device drivers within its protected memory area since it is loaded first. It is not re-written by applications etc.. it is just a device driver that allows for device drivers to be loaded and controled by the vmm32 device driver. If you are having problems replace it as ahood explains but if you are getting VMM errors, you will likely find that a device driver is causing a conflict within the device manager. VXD's are loaded from the registry under HKLM\System\CurrentControlSet\Services\VXD.


Expert Comment

ID: 1727387
Windows 95 provides an option for verifying installed components when Setup detects an existing Windows 95 installation. When you use the Verify option, Setup reads SETUPLOG.TXT for the installed components and reruns the Setup process to verify all system components. If Verify fails as a result of a missing or damaged file, Setup reinstalls the file. As part of this verification, Setup rebuilds VMM32.VXD and recopies any required files. It should not effect any of your installed apps to do this.


Author Comment

ID: 1727388
thanks, everyone.  

Sgenther---the Verify sounds like wht we want, but it's not being offered as an option.  I found an MS tech note that explains what Win95 looks for in SETUPLOG.TXT to decide whether to run verify.  I forwarded the note to my friend who has the problem.

durcaj01- I'd love to undo my misconceptions.  What I gather so far from the Resource Kit is that VMM32.VXD is custom-created by SETUP at install time based on its assessment of the PC's hardware configuration, using a bare-bones version of VMM32.VXD that's extractable from the CABs.  My friend's version of this file has a modify date that's earlier than the creation date, and the system boots to either safe mode or direct to shutdown prompt.  So our current suspicion is corruption here.....though BOOTLOG shows the last thing to be font load stuff.



Accepted Solution

sgenther earned 600 total points
ID: 1727389
If you run Setup over an existing Windows 95 installation, you
       receive the following two options:
        - Restore Windows files that are changed
        - Copy all Windows files again
     Both of these options verify the validity of Windows 95 files.
       Verifying the Windows 95 files takes as long as an original
       installation because Setup must open each cabinet file to
       verify the Windows 95 files. Setup uses the Setuplog.txt file
       to determine which files to check and marks each good file with
       an "S." This mode also rebuilds the Vmm32.vxd file and recopies
       any file with a lost long filename.


Author Comment

ID: 1727390
Thanks for the information.  My friend compared his files to a backup and found that it was actually another VXD, NDIS-related, which was corrupt.  It worked when he replaced this one file.  I still don't understand why Setup didn't offer him the verify option, but perhaps there were some problems also with SETUPLOG.TXT.

In any event, he's up and running without reinstalling all the apps!  I'll make sure he sees your responses.  Thanks again to you all.


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