Skip navigation

JSI Tip 3038. What is the Windows 2000 Application Compatibility Tool?

Apcompat.exe tries to convince a program that performs compliance checking that it is actually running on an earlier operating system, by passing a different version number.

Apcompat.exe generally helps when you receive messages like:

This program requires Windows 95 to run.

This application requires Windows NT Service Pack 3 or higher.

Apcompat.exe does NOT help with:

Programs that attempt to access the hardware directly.

W9x programs that use virtual device drivers (VXDs).

Apcompat.exe may help with:

Programs that were written for Windows NT and require a particular service pack.

W9x games that rely on DirectX.

The Apcompat.exe tool is located in the Support folder on the Windows 2000 CD-ROM.

Note: The Help button does not work unless you install the Windows 2000 Support Tools.

You must install the program to get the following documentation:

Support Tools Documentation

Application Compatibility Program (Apcompat.exe)

This program is designed to overcome the most common causes of application incompatibility
with Windows 2000. You can use this tool with a Windows interface by running the 
Application Compatibility program, or you can run this program as a command-line tool.

To use the Application Compatibility program, 
Click Browse and specify the executable (.exe) file for the program you want to run.

Specify any of the Application Compatibility settings, and then click OK.

Operating System Version Checking

While installing or running, some programs check which operating system version you are running.
If the program is designed to run on only certain operating systems, and Windows 2000
is not one of them, you are prevented from installing or running the program.

If you encounter such a problem, try installing or running the program from the 
Application Compatibility program.
Under Operating system, specify the operating system on which you previously ran the program.

When the program checks the version of the operating system, the operating system
you specified is returned.
If the program installs successfully, verify that the program also runs successfully.

If the original error occurs again, the program is incompatible and cannot be run on Windows 2000.
Contact the maker or vendor of the program and inquire about an upgrade version. 

Memory Management Conflicts

Some programs use memory in ways that can conflict with Windows 2000 improved memory management.
If errors occur while running a program on Windows 2000 that did not occur on your previous 
operating system, try disabling the Heap Manager for the portion of memory reserved for the program.

Select the Disable Heap Manager on Windows 2000 check box. A program running with the 
Heap Manager disabled can avoid conflicts with Windows 2000 memory management, but also uses 
memory less efficiently. 

Temp Folder Path Incompatibility

Some programs allocate a limited number of characters to store the path and name of the Temp folder.
If the number of characters used to identify the Temp folder on Windows 2000 is greater than the 
length allowed by a program, select the Use the pre-Windows 2000 temp path check box to specify 
a non-Windows 2000 Temp folder.

The specified program then uses \Temp for the Temp folder. If this folder does not exist,
it is created. 

Correct Disk Space Detection

Some applications use a different data type than Windows 2000 to store the amount of 
free disk space available on your computer. This can result in an application determining
that there is not enough disk space to run or perform an operation.

To resolve such a discrepancy in disk space detection, select the Correct disk space detection
for 2-GB+ drives check box. 

Store Application Compatibility Settings

If you resolve a compatibility problem by using any of the options in Application Compatibility,
you can make these settings permanent. Then you can run the specified application without using 
the Application Compatibility program.

To save the Application Compatibility settings for the specified application,
select Make the above check box settings permanent. This saves the settings in the registry.
Product Compatibility


Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.