Out of Environment Space Error Message in MS-DOS Programs

When you attempt to run an MS-DOS program in Windows, you may receive the following error message:

This issue can occur if you do not have enough memory in the MS-DOS environment to set an environment variable.

To resolve this issue, increase the default environment space available for MS-DOS programs. To do this, use one of the following methods.

Modify the Environment for All MS-DOS Programs

To increase the default environment space for all MS-DOS programs running in Windows, edit the Shell command in the Config.sys file. To do this, follow these steps:

1. Click Start, and then click Run.
2. In the Open box, type sysedit, and then click OK.
3. Click the Config.sys window.
4. At the beginning of the Shell= line, type REM, and then press the SPACEBAR.
   
   If the Shell= line does not exist, proceed to the next step.
5. Press the HOME key.
6. Type the following line to create a new Shell= line, and then press ENTER:
   SHELL=C:\COMMAND.COM /E:4096 /P
7. On the File menu, click Save.
8. On the File menu, click Exit.
9. Restart the computer.

Modify the Environment for a Specific MS-DOS Program

To increase the default environment space for a specific MS-DOS program, follow these steps:

1. Right-click the MS-DOS program icon, and then click Properties.
2. Click the Memory tab.
3. In the Initial Environment box, type the number of kilobytes (KB) that the program requires, and then click OK.
   
   NOTE: The maximum amount of memory that you can allocate for an MS-DOS program is 4096 KB.