The File Extensions Database

.DEM File Extension

  • Developer by: Valve
  • Category: Game Files
  • Format: Binary

What is an .DEM file?

.DEM is Video Game Demo File

A DEM file is a game replay file created by various first-person shooter games and most popularly by Counter-Strike (supported by Valve's Source game engine). DEM files are used to record a player's perspective in a single or multiplayer game, which can then be shared with others.

To play a Counter-Strike DEM file in Windows, first place it in the cstrike\ installation directory. Next, start Counter-Strike and open the console window. From the console window, type viewdemo demoname, where "demoname" is the filename without the ".dem" extension.

DEM files are also used by Hexen II, Quake, and Unreal Tournament. However, the files are only playable on the game for which the demo was created.

NOTE: DEM files created by Source engine games, such as Counter-Strike, can be opened in VirtualDub to play the video frame sequence and record it to other output formats, such as .AVI. There is a size limitation of 2 GB for AVI videos created by Valve's source engine. You can install the Apple QuickTime component to encode the .H264 codec in order to avoid the size limitation.

Programs that open Video Game Demo File
Valve Counter-Strike
Epic Games Unreal Tournament
id Software Quake
id Software Hexen 2
Valve Counter-Strike
Epic Games Unreal Tournament
id Software Quake
File Type 2 Digital Elevation Model
Developer by: USGS Category: GIS Files

Contains mapping data with elevation information; used by the US Geological Survey.

Programs that open Digital Elevation Model
ESRI ArcGIS for Desktop
Golden Software Voxler
TatukGIS Viewer
MicroMouse AccuTrans 3D

How to solve problems with DEM files

  • Associate the DEM file extension with the correct application. On :
    Windows: Right click on any DEM file and then click "Open with" > "Choose another app". Now select another program and check the box "Always use this app to open *.DEM files". Mac: Right click (or Ctrl-click) the DEM 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 .DEM is Video Game Demo File. Because only the current version supports the latest DEM file format. Search, therefore, e.g. on the Valve manufacturer website after an available .DEM is Video Game Demo File update.
  • To make sure that your DEM file is not corrupted or virus-infected, get the file again and scan it with antivirus software.