This article describes how to troubleshoot the following problems with
DriveSpace in Windows 95:
- DriveSpace displays an error message
- Your computer stops responding (hangs) during compression
- Your computer does not boot properly after compressing a drive
DriveSpace Displays an Error Message
If you receive an error message while running DriveSpace, check the
Microsoft Knowledge Base for existing articles about that error message.
Some of the most common errors are:
DriveSpace Err Msg: Mini.cab File Is Missing or Damaged...
Err Msg: Drive C Contains Errors That Must Be Corrected...
Windows 95 DriveSpace Err Msg: Windows Cannot Perform...
Err Msg: Windows Has Detected a Compressed Drive Access
DriveSpace VxD and Real-Mode Driver Are Mismatched
Error Message: ID Number DRVSPACE125
Error Message: Mini.cab Is Missing or Corrupt
Computer Hangs During Compression
If your computer hangs while DriveSpace is running, follow these steps:
- If DriveSpace stops when it is 25 percent finished, see the following
article in the Microsoft Knowledge Base:
DriveSpace May Fail to Start in Mini-Windows Mode
- If DriveSpace stops when it is between 25 and 100 percent finished, see
the following article in the Microsoft Knowledge Base:
DriveSpace Restartability in Windows 95 and MS Plus!
- If DriveSpace stops while you are uncompressing or resizing a
compressed drive, follow these steps:
- Start your computer with your Windows 95 or Microsoft Plus! Startup
disk. When you see the "Starting Windows 95" message, press the F8
key, and then choose Step-By-Step Confirmation from the Startup
menu. Press N when you are prompted to load the DoubleSpace or
NOTE: If you did not create a Startup disk during Windows 95 Setup,
or you did not update your Startup disk during Microsoft Plus!
Setup, you can create a Startup disk manually.
For information about creating or updating a Startup disk, please
see the following articles in the Microsoft Knowledge Base:
IMPORTANT: If your computer uses software that translates disk
geometry (such as OnTrack Disk Manager or Micro House EZ-Drive),
make sure to load the translation software when you start your
computer with the Startup disk.
Problems Using Windows 95 or Microsoft Plus! Startup
Manually Updating the Startup Disk After Installing
- Verify that you have the correct DriveSpace and ScanDisk files on
drives A and C.
Check the Startup disk for the correct Drvspace.bin and Scandisk.exe
files with the following commands:
dir /a a:\drvspace.bin
NOTE: The Startup disk does not contain a Dblspace.bin file. The
Drvspace.bin file should have the file size and date noted below,
depending on whether or not Microsoft Plus! is installed. If you did
not install Microsoft Plus!, the Scandisk.exe file should be 134,738
bytes in size. If you installed Microsoft Plus!, the Scandisk.exe
file should be 137,836 bytes in size.
If you do not have the correct versions of these files, extract new
copies from your original disks or CD-ROM to the root folder of
For information about using the Extract tool, please see the
following article in the Microsoft Knowledge Base:
Make sure that both the Drvspace.bin and Dblspace.bin files exist in
the root folder of drive C. To check for these files, type the
How to Extract Original Compressed Windows Files
dir /a c:\d??space.bin
If you did not install Microsoft Plus!, you should see the following
If you did install Microsoft Plus!, you should see the following
File name Date/Time Size
Drvspace.bin 07-11-95 9:50 A.M. 71,287
Dblspace.bin 07-11-95 9:50 A.M. 71,287
If you are using Windows 95 OEM Service Release 2, you should have
the following files whether or not Microsoft Plus! is installed:
File name Date/Time Size
Drvspace.bin 07-14-95 12:00 A.M. 64,135
Dblspace.bin 07-14-95 12:00 A.M. 64,135
IMPORTANT: Drvspace.bin and Dblspace.bin are the same files with
different names. Copy the Drvspace.bin file to Dblspace.bin on the
Startup disk with the following commands before you proceed:
File name Date/Time Size
Drvspace.bin 08-24-96 11:11 A.M. 65,271
Dblspace.bin 08-24-96 11:11 A.M. 65,271
attrib -s -h -r a:\drvspace.bin
copy a:\drvspace.bin a:\dblspace.bin
attrib +s +h +r a:\d??space.bin
- Make sure that either a Drvspace.ini or Dblspace.ini file exists in
the root folder of drive C. To check, type the following command:
dir /a c:\d??space.ini
- If neither a Drvspace.ini or Dblspace.ini file exists on the hard
disk, create one using the EDIT command from the Startup disk. To do
this, type edit c:\drvspace.ini, and then
press ENTER. Then, save the Drvspace.ini file and close the editor.
- Restart your computer and do not press the F8 key. The computer
should boot into Windows 95 and the contents of the compressed drive
should be available.
Check for a Restart.drv file in the root folder of drive C or its
host drive by typing the following command:
dir /a <drive>:\restart.drv
This file is required by DriveSpace to restart a failed operation.
If the Restart.drv file exists, copy the Config.pss and Autoexec.pss
files from the Failsafe.drv folder to the root folder of the
physical boot drive by typing the following commands at a command
copy <drive>:\failsafe.drv\config.pss <drive>:\config.sys
Then, edit the Drvspace.ini or Dblspace.ini file and place a
semicolon (;) before the "ActivateDrive" line for compressed drive C
(if it is being mounted). For example,
copy <drive>:\failsafe.drv\autoexec.pss <drive>:\autoexec.bat
This causes the computer to boot to the physical boot drive
containing the Failsafe.drv folder and the Restart.drv file.
NOTE: If there are multiple "ActivateDrive" lines that reference
drive C, place the semicolon before the line that ends with "C0."
The Drvspace.ini file is a hidden, system, read-only file stored in
the root folder of the physical boot drive. To edit the file you
must first remove the Hidden, System, and Read-Only attributes. To
do so, type the following line at a command prompt:
attrib -s -h -r <drive>:\d??space.ini
Restart your computer and DriveSpace should try to complete the
failed operation in mini-Windows mode.
- If the Restart.drv file does not exist, DriveSpace cannot restart
the failed operation automatically. Format the drive and restore
data from a recent backup, or contact Microsoft Technical Support
for additional assistance.
NOTE: It may be impossible to recover data at this point. It may be
necessary to format the drive and restore from a recent backup or
to reinstall Windows 95.
- If you are troubleshooting a problem with one of the following
DriveSpace operations that was not completed successfully, these
operations can be continued after the underlying problems are resolved
(provided you have not made manual changes to the DriveSpace
configuration, such as changing an .ini file setting or renaming a
- Compressing an existing drive
- Uncompressing a DoubleSpace or DriveSpace drive
- Creating a new, empty DriveSpace drive
- Changing the size of a DoubleSpace or DriveSpace drive
- Changing the estimated compression ratio (ECR) for a DoubleSpace
or DriveSpace drive
- Mounting a DoubleSpace or DriveSpace drive
- Upgrading (converting) a DoubleSpace or DriveSpace drive to
- If you are not troubleshooting a problem with one of the DriveSpace
operations listed above, verify that the compressed drive is mounted by
trying to access the drive letter that was created when you originally
compressed the drive.
For example, if you compressed drive C and DriveSpace created drive
letter H for the host drive, type h: and
press ENTER. If you receive an "Invalid drive specification" error
message, the compressed drive is not mounted.
- Use ScanDisk to repair or mount the unmounted CVF. To do so, type the
where drive is the letter of the compressed drive if it was mounted
in step 5, or type
where YYY is the extension of the unmounted CVF and drive is
the drive containing the CVF.
When you are prompted to check the host drive first, do so. Perform a
surface scan on all drives, and fix any errors found.
If you receive an error message stating that you cannot use compressed
drive C because it is not mounted, restart your computer and then
repeat step 5.
NOTE: If there is insufficient memory available for ScanDisk to check
the compressed drive, repeat the command after modifying your Startup
disk to load the compression driver in upper memory. To do so, create
a Config.sys file on the Startup disk that includes at least the
where <drive> is either drive C or its host drive. The Failsafe.drv
folder is a hidden folder on the physical boot drive that is used by
DriveSpace to restart interrupted disk compression operations. This
folder should be available even if your compressed drive is not
The Failsafe.drv folder may also contain a Config.emm file that can be
used to optimize conventional memory. However, you must change the
drive letter designation on the "device=" and "devicehigh=" lines to
reference the host for drive C if drive C is a compressed drive that
is mounted when you boot with the Startup disk.
IMPORTANT: If your hardware configuration requires upper memory to be
excluded when using Emm386.exe, include the appropriate "x=mmmm-nnnn"
syntax on the Emm386.exe command line.
- Scan your computer for viruses using the latest anti-virus software
available to you. If you upgraded from Microsoft MS-DOS 6.0 or later
and you have Microsoft Anti-Virus for MS-DOS installed, run Msav.exe
to detect and clean all logical drives.
WARNING: The presence of a computer virus may lead to partial or
complete data loss when you perform the following troubleshooting
steps. For additional information about computer viruses, please see
the following article in the Microsoft Knowledge Base:
Description of Computer Viruses
- Perform a thorough surface scan on your hard disk. To do so, follow
- Edit the Scandisk.ini file on the Startup disk to include the
- Save and close the Scandisk.ini file.
- Type the following line to scan the hard disk
where <drive> is the compressed drive, if it is mounted. If the
compressed drive is not mounted, use the host drive letter instead.
Note that the host drive letter is the same as the drive letter you
normally use for the compressed drive (when you are not having a
problem with the compressed drive).
When you are prompted, instruct ScanDisk to perform the following
NOTE: This procedure may take some time, particularly if you have a
large hard disk or more than one hard disk. To automate this
procedure so that ScanDisk does not prompt you for instructions,
include the following lines in the Scandisk.ini file:
- check the host drive first
- mount any unmounted CVFs
- perform a surface scan on both drives
- fix all errors found
- view, and save, a log file
Then, run ScanDisk using the following command:
LfnCheck = Off
Mount = Always
DriveSummary = Off
AllSummary = Auto
Surface = Always
CheckHost = Always
SaveLog = Overwrite
Undo = Never
DS_Header = Fix
FAT_Media = Fix
Okay_Entries = Fix
Bad_Chain = Fix
Crosslinks = Fix
Boot_Sector = Fix
Invalid_MDFAT = Fix
DS_Crosslinks = Fix
DS_LostClust = Fix
DS_Signatures = Fix
Mismatch_FAT = Fix
Bad_Clusters = Fix
Bad_Entries = Delete
LostClust = Save
scandisk <drive>: /custom
ScanDisk creates a Scandisk.log file that you can examine to determine
whether ScanDisk fixed any problems on the drive. The problem should
now be resolved unless you are troubleshooting a failed DriveSpace
operation that is restartable. If this is not the case, you may want
to review the troubleshooting steps.
Your Computer Does Not Boot Properly After Compressing a Drive
A compressed drive may not be mounting correctly. To troubleshoot this
problem, follow steps 5-8 above.
If the compressed drive is mounted correctly but Windows 95 still does not
load, see the following article in the Microsoft Knowledge Base:
Troubleshooting Windows 95 Startup Problems and Error