This information applies to both Microsoft DoubleSpace and Microsoft
DriveSpace. For MS-DOS 6.22, use DRVSPACE in place of DBLSPACE for
commands and file names.
The DoubleGuard Alarm message reads as follows
DoubleGuard Alarm #<nn>
A program has corrupted memory belonging to DoubleSpace.
Further disk activity could result in the loss of some or all of
the data on your drive. Therefore, DoubleGuard has halted your
computer. For more information, see the README.TXT file
where <nn> is 13, 14, 15, or 16.
These errors occur when DoubleSpace detects that a software application,
device driver, or terminate-and-stay-resident (TSR) program has corrupted
memory used by DBLSPACE.BIN.
DoubleGuard Alarm Number Area Corrupted
13 BitFAT buffer
14 MDFAT buffer
15 File Fragment List
16 DBLSPACE.BIN Code Block
The following programs are known to cause a DoubleGuard Alarm errors:
Program More Information
Qemm (in Stealth mode) Contact Quarterdeck Office Systems for
Vertisoft SpaceManager 1.53 Causes DoubleGuard error #15 when used
on a 286 machine running MS-DOS 6.2
Text from the MS-DOS 6.2 README.TXT:
7.19 You receive a DoubleGuard Alarm message
If a DoubleGuard Alarm message appears, DoubleGuard has detected that
an application has damaged memory that DoubleSpace was using.
DoubleGuard halts your computer to prevent any further damage to your
Normally, each program "owns" a separate area of memory, and does not
use memory that another program is already using. However, a few
programs contain programming errors that cause them to inadvertently
use memory belonging to another program. If such a program
inadvertently uses memory belonging to DoubleSpace, that program could
write its own data over the data DoubleSpace was storing there. Since
the data that DoubleSpace stores in memory usually includes files you
are currently using, this could cause damage to your data.
DoubleSpace's DoubleGuard safety-checking feature detects when another
program has violated DoubleSpace's memory, and immediately shuts down
your computer to minimize the chance of data loss. (If further disk
activity were to occur instead, you could lose some or all of the data
on your drive, since the data DoubleSpace has in memory is probably
invalid due to damage by the other program.)
If you receive a DoubleGuard Alarm message, do the following:
• Restart your computer by turning the power switch off and then
• Type the following at the command prompt:
NOTE: If you are using Windows 95, restart your computer to a command
prompt before typing this line.
This runs ScanDisk on all your drives to detect and correct any
problems that might have been caused by the program that violated
• Make a note of which program, if any, you were running when the
DoubleGuard Alarm occurred. That program is probably (but not
necessarily) the program that caused the DoubleGuard Alarm.
If you receive additional DoubleGuard Alarms, take notes about
what you were doing and see if you can detect a pattern.