This article was previously published under Q134859
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If you install, remove, and then reinstall Windows 95, you may receive thefollowing error message when you start Windows 95:
The DriveSpace VxD and the DriveSpace real-mode driver are mismatched. You may need to reinstall them.
Press any key to continue.
When you press a key, Windows 95 starts, but it may be unstable. You maysee unusual characters on the screen and you may receive "fatal exception"error messages.
DriveSpace 3 from Microsoft Plus! for Windows 95 places real-mode driverson the hard disk that are not removed when you delete the Windows folder.When you reinstall Windows 95, Setup places a DriveSpace VxD in theIosubsys folder that is incompatible with the DriveSpace 3 drivers.
Replace the Drvspacx.vxd file in the Iosubsys folder with the correctversion from the original Microsoft Plus! disks or CD-ROM. To do so,follow these steps:
Restart your computer. When you see the "Starting Windows 95" message, press the F8 key, and then choose Command Prompt Only from the Startup menu.
Change to the Windows\System\Iosubsys folder.
Rename the Drvspacx.vxd file to Drvspacx.old.
Extract the Drvspacx.vxd file from the Microsoft Plus! CD-ROM or original disks to the Iosubsys folder. The Drvspacx.vxd file is located in the Plus_1.cab file on both the Microsoft Plus! disks and CD-ROM.
Use the following command to extract the Drvspacx.vxd file
where <destination> is the Windows\System\Iosubsys folder and <drive> is the drive containing the Microsoft Plus! disk or CD-ROM.
For information about the Extract tool, type "extract" (without quotation marks) at a command prompt, or see the following article in the Microsoft Knowledge Base:
129605 How to Extract Original Compressed Windows Files
Restart your computer normally.
If you still receive a "mismatch" error message when you restart yourcomputer and the Drvspace.bin file is the correct Microsoft Plus! version,check for a Dblspace.bin file dated 7/11/95 or earlier. This file is ahidden file in the root folder of the boot drive. If this file exists,rename it to Dblspace.old and then restart your computer. DriveSpace 3does not require the Dblspace.bin file to mount compressed volumes, butWindows 95 processes Dblspace.bin before Drvspace.bin if both files exist.
This behavior can also occur if you reinstall Windows 95 to a differentfolder than its original folder after you install Microsoft Plus!. If youreinstalled Windows 95 in a different folder and you want to use theoriginal installation, edit the Msdos.sys file on both the host drive andthe compressed drive. Make sure that the PATH statement points to thecorrect folder. After you edit the Msdos.sys files, save the files andthen restart your computer.
NOTE: If you are using a Microsoft Plus! CD-ROM and you are not usingreal-mode CD-ROM drivers, this resolution does not work.
The following tables list the correct files.
Windows 95 without Microsoft Plus!:
File name Date/Time Size LocationDrvspace.bin 07-11-95 9:50am 71,287 C:\ and root of compressed driveDblspace.bin 07-11-95 9:50am 71,287 C:\ and root of compressed driveDrvspacx.vxd 07-11-95 9:50am 54,207 C:\windows\system\iosubsys
Windows 95 with Microsoft Plus!:
File name Date/Time Size LocationDrvspace.bin 07-14-95 12:00am 64,135 C:\ and root of compressed driveDblspace.bin 07-14-95 12:00am 64,135 C:\ and root of compressed driveDrvspacx.vxd 07-14-95 12:00am 61,719 C:\windows\system\iosubsys
Windows 95 OEM Service Release 2:
File name Date/Time Size LocationDrvspace.bin 08-24-96 12:00am 65,271 C:\ and root of compressed driveDblspace.bin 08-24-96 12:00am 65,271 C:\ and root of compressed driveDrvspacx.vxd 08-24-96 11:11am 57,466 C:\windows\system\iosubsys