This article describes the relationship of .CPL files and the icons that
appear in the Microsoft Windows and Microsoft Windows for Workgroups
Control Panel. This article includes information on the following:
- A general description of .CPL files
- How to replace Control Panel icons
- A list of the default .CPL files shipped with Windows
- What to do if you receive a "Cannot Find Components" message
- How to use the Windows 3.1 icons elsewhere
- Multimedia settings in the CONTROL.INI file
- Possible general protection (GP) faults in the Control Panel
Description of .CPL Files
You can add additional icons and functionality to the Control Panel in
Windows 3.1 and Windows for Workgroups versions 3.1 and 3.11 by adding
"installable" .CPL files. These .CPL files must be located in the
Windows SYSTEM directory or the corresponding icon does not appear in
the Control Panel. However multimedia .CPL files can be referenced in
another directory by specifying a new path in the [MMCPL] section of
the CONTROL.INI file.
You should design and structure the .CPL file to conform to the
CPLINFO specification as outlined in the Microsoft Windows
Programmer's reference. Simply attaching a .CPL extension to a file of
unspecified format doesn't work. The CPLINFO specification contains
information concerning the icon, application or device name,
identification numbers, and other data.
NOTE: If VER.DLL is missing from the WINDOWS or Windows SYSTEM
directory, only the 386 Enhanced icon and the Sound icon appear in
Replacement of Control Panel Icons
When you run the Control Panel in Windows 3.1 or Windows for
Workgroups (WFWG), some of the icons may not display if the
corresponding .CPL file is corrupt or missing. To correct this
problem, you must expand the files from the Windows disks back to the
Windows SYSTEM directory. Note that the network icon does not display
if the network is not properly installed. This is not a problem with
the MAIN.CPL, but with the network installation.
Use the following steps to add a missing Control Panel icon:
- Exit Windows.
- Copy EXPAND.EXE from your Windows or WFWG disk to your WINDOWS
NOTE: EXPAND.EXE is located on Windows 3.1 disk 3 (both disk sizes),
on WFWG 3.1 disk 8 (5.25) or disk 6 (3.5), and on WFWG 3.11 disk 6
(both disk sizes).
- Put the Windows disk with the correct *.CP_ file in your floppy
disk drive. Depending on the Windows version and disk size you have,
*.CPL files are located on the following disks:
Windows 3.1 3.5" Disk 5.25" Disk
CPWIN386.CP_ Disk 1 Disk 1
DRIVERS.CP_ Disk 4 Disk 5
MAIN.CP_ Disk 4 Disk 5
SND.CP_ Disk 4 Disk 6
WFWG 3.1 3.5" Disk 5.25" Disk
CPWIN386.CP_ Disk 2 Disk 2
DRIVERS.CP_ Disk 6 Disk 7
MAIN.CP_ Disk 3 Disk 5
SND.CP_ Disk 7 Disk 8
WFWSETUP.CP_ Disk 2 Disk 2
WFWG 3.11 3.5" Disk 5.25" Disk
CPWIN386.CP_ Disk 2 Disk 2
DRIVERS.CP_ Disk 5 Disk 6
FAX.CP_ Disk 6 Disk 4
MAIN.CP_ Disk 3 Disk 3
SND.CP_ Disk 6 Disk 8
- Type the following at the MS-DOS command prompt
expand A:\xxxxx.CP_ C:\WINDOWS\SYSTEM\xxxxx.CPL
where xxxxx is the name of the file and drive A is the drive
containing the floppy disk with the .CPL files.
- Reopen the Control Panel (it is not necessary to exit Windows
because the Control Panel performs its search for .CPL files when it
Default .CPL Files Shipped with Windows 3.1
Windows 3.1 ships with the following four "installable" Control Panel
Name Size Name Size Icon
CPWIN386.CP_ 48841 CPWIN386.CPL 104816 Control Panel's 386
Enhanced Mode icon
DRIVERS.CP_ 21385 DRIVERS.CPL 41440 Control Panel's Drivers
icon for installing and
MAIN.CP_ 89396 MAIN.CPL 148560 Control Panel's
Network (if installed)
SND.CP_ 4986 SND.CPL 8192 Control Panel's Sound
icon, which allows you
to assign sounds to
many system events
NOTE: The Windows Driver Library disks include an additional .CPL
file, SBPMIXER.CPL (file size 25792, dated 2/1/92), for computers with
Creative Labs Sound Blaster Pro sound cards. This icon is an
audio-mixing board for the Sound Blaster Pro.
"Cannot Find Control Panel Components" Error Message
The Windows 3.1 or Windows for Workgroups 3.1 and 3.11 Control Panel
(CONTROL.EXE) may return the following message upon execution:
Cannot find the Control Panel components (files
with .CPL extension).
Verify that they are installed in your Windows
This error usually occurs when the .CPL files cannot be found in the
SYSTEM directory, or if the files have become corrupt. First, you
should confirm existence of the following .CPL files in your Windows
WFWSETUP.CPL <=== Windows for Workgroups version 3.1 only.
If any file is missing, you need to expand it from your Windows disks.
If all files are there, then it is possible that the files are
corrupted. In this case you should exit Windows, delete all of the
SYSTEM\*.CPL files, then expand each .CPL from your Microsoft Windows
disks into your Windows SYSTEM subdirectory, as described in this
Using a .CPL File Icon Elsewhere
The Windows version 3.1 Control Panel contains only one icon embedded
in the executable file CONTROL.EXE. If an embedded icon from the
Windows 3.0 CONTROL.EXE file is used as a replacement icon for a
program item, a similar Windows 3.1 icon may be located in one of the
Control Panel data files (*.CPL).
Because of the modular structure of the Windows 3.1 Control Panel,
most icons that were embedded in earlier versions of the CONTROL.EXE
file have been moved to different associated data files located in the
SYSTEM subdirectory. These files include CPWIN386.CPL, DRIVERS.CPL,
MAIN.CPL, and SND.CPL. To use one of the icons placed in the .CPL
files for a program item in Windows 3.1, use the following steps:
- In Program Manager, select the program item whose icon needs to
- From the File menu, choose Properties to open the Program Item
Properties dialog box.
- Choose the Change Icon button.
- Type the appropriate .CPL filename in the File Name box, then
choose the OK button.
Multimedia Settings in the CONTROL.INI
The [MMCPL] section of the CONTROL.INI file contains information which
concerns the size and placement of the Control Panel window, the
number of iconized applications in the Control Panel, and a path
setting for multimedia .CPL files residing outside of the Windows
SYSTEM subdirectory. The settings include:
x=<number> Horizontal window coordinate
y=<number> Vertical window coordinate
h=<number> Height in pixels
w=<number> Width in pixels
numapps=<number> The number of applications in the
In addition Microsoft Windows for Pen Computing may add the following
lines to the [MMCPL] file:
These entries allow the Control Panel to find .CPL file in
subdirectories other than the Windows SYSTEM subdirectory.
GP Faults in Control Panel
If you experience general protection (GP) faults when opening Control
Panel, it is likely that one of the .CPL files is corrupted or
damaged. Please follow the instructions in the previous section of
this article to replace the icon.
Missing Control Panel Icons
If KRNL386.EXE is in the Windows directory instead of, or in addition to,
the Windows\SYSTEM subdirectory, one or more of the Control Panel icons
may not appear. KRNL386.EXE should be in only the Windows\SYSTEM
"Microsoft Windows Programmer's Reference, Volume3: Messages,
Structures, and Macros," version 3.1, pgs. 260, 543-549.
"Microsoft Windows for Pen Computing: Programmer's Reference,
Windows Software Development Kit," version 3.1, pgs. 288-289.