The File Extensions Database

.COM File Extension

  • Developer by: Microsoft
  • Category: Executable Files
  • Format: Binary

What is an .COM file?

.COM is DOS Command File

A COM file is an executable program capable of being run by MS-DOS and Windows. It is saved in a binary format and is similar to an .EXE file, but differs in that it has a maximum size of roughly 64KB and it has no header or metadata. COM files are commonly used for executing a set of instructions whereas EXE files are used for fully developed programs.

Both DOS and Windows have used the ".com" extension for many years, and the ".com" extension shouldn't be confused with the ".com" Internet domain name.

NOTE: If a folder includes both EXE and COM files with the same filename (e.g., run.exe and, the DOS or Windows command prompt will run the COM file if you type the filename without the extension.

Common COM Filenames

COMMAND.COM - The Windows shell program used by DOS and Windows 95, 98, and Me. It was replaced by cmd.exe in later versions of Windows.

Programs that open DOS Command File
Microsoft Windows
Parallels Desktop for Mac with Windows installed

How to solve problems with COM files

  • Associate the COM file extension with the correct application. On :
    Windows: Right click on any COM file and then click "Open with" > "Choose another app". Now select another program and check the box "Always use this app to open *.COM files". Mac: Right click (or Ctrl-click) the COM file, then click "Open with" > "Other...". Then choose another program and check the "Always Open With" box. Linux: Right click on the file, and select "Open with" and choose another program. iPhone: Tap the file. If you do not see an app to open the file, then tap Share "Share" and choose an app. Alternatively, save the file. Then open the Files app Files app. There long-press on the file, then release your finger. You will see a black menu bar. Then tap "Share" and select an app. Android: Tap the Settings icon on your smartphone, then tap on the Apps section. There tap the Options icon in the top right-hand corner of the screen to change the default apps.
  • Update your software that should actually open .COM is DOS Command File. Because only the current version supports the latest COM file format. Search, therefore, e.g. on the Microsoft manufacturer website after an available .COM is DOS Command File update.
  • To make sure that your COM file is not corrupted or virus-infected, get the file again and scan it with antivirus software.