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X-COM: UFO Defense

From PCGamingWiki, the wiki about fixing PC games

This page is for the original game. For the reboot, see XCOM: Enemy Unknown.

X-COM: UFO Defense
X-COM: UFO Defense cover
Mythos Games
Japan Spectrum HoloByte
Current 2K Games
Release dates
DOS March 1994
Windows 1998
Windows (DOSBox) September 4, 2008
Monetization One-time game purchase
Modes Singleplayer
Pacing Turn-based
Perspectives Bird's-eye view, Isometric
Controls Point and select
Genres Strategy
Themes Sci-fi
Series X-COM
X-COM: UFO Defense on HowLongToBeat
X-COM: UFO Defense on IGDB
X-COM: UFO Defense guide on StrategyWiki
X-COM: UFO Defense on MobyGames
X-COM: UFO Defense on Wikipedia
X-COM: UFO Defense 1994
X-COM: Terror from the Deep 1995
X-COM: Apocalypse 1997
X-COM: Interceptor 1998
X-COM: Email games 1999
X-COM: Enforcer 2001
XCOM: Enemy Unknown 2012
The Bureau: XCOM Declassified 2013
XCOM 2 2016
XCOM: Chimera Squad 2020

Key points

Use OpenXcom for many new features, which is also highly moddable.
Also released as UFO: Enemy Unknown and X-COM: Enemy Unknown.

General information Community Discussions for game series Support Page
Steam Community Discussions
UFOpaedia - Wiki for the game.
StrategyCore - The largest and oldest community for the game. - Fan site with good FAQ and downloads.


Source DRM Notes Keys OS
Prompts for answers from manual, code wheel, etc.
Use OpenXcom or DOSBox. Use UFO 1.4 to remove code prompts.
DRM details are not known
Collector's Edition
Gamesplanet logo.svg
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DOS 1.4 pre-packed with DOSBox
Green Man Gaming
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Humble Store
Included in X-COM: Complete Pack, with X-COM: Terror from the Deep, X-COM: Apocalypse, X-COM: Interceptor and X-COM: Enforcer.
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Includes both DOS 1.4 and CE merged together; DOS runs though DOSBox
GamersGate (unavailable)
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A free demo version is available from

Version differences

The US version (UFO Defense) comes pre-patched to version 1.2.
The Collectors Edition ("Gold") is Windows native and, thus, won't run in DOS. It also is fully patched to 1.4 and has the difficulty and hanger split in half bugs fixed but introduces the blaster bomb bug and base facility dismantle-construction crash.[1]

Essential improvements

This section may require cleanup to meet basic quality standards. The specific problem is: Abbreviate.. You can help by modifying the article. The discussion page may contain useful suggestions.
The following tweaks are only available by using OpenXcom.


An open-source, multi platform remake with various improvements.[2][1]
Unlimited save games support, along with native widescreen support and proper audio formats.
DOSBox no longer required, simply copy the new OpenXcom files where the main executable is located or use the provided installer.

Skip intro videos

Skip Intro[citation needed]
  1. Go to the Options menu and then go to Advanced.
  2. Uncheck Play intro.

Track Steam playtime

Instructions[citation needed]
  1. Go to <path-to-game>\X-Com UFO Defense\XCOM\
  2. Rename dosbox.exe to something else, then rename OpenXcom.exe to dosbox.exe

Original MS-DOS and CE


UFO 1.4 updates the game to the latest version and removes the copy protection. Digital versions come pre-updated making this unnecessary on them.
AI Patch unofficial patch that fixes several bugs in the enemy AI making them more effective. Warning to new players: makes the game more difficult. If you're on CE and using UFO Extender then this fix is unnecessary as it already includes one of its own.
Polar Terrain Footstep Fix reintroduces the snow footstep sound on the polar terrain that was broken in patch 1.4; works on CE and somewhat untested on DOS.
Run with UFO Extender plus XcomUtil[3]
UFO Extender is CE version only. XcomUtil however works on both versions. If you only have the DOS version you can replace some of UFO Extender's functionality with BaseFixer: info on getting Python working in DOSBox is available here and a modified linker for XcomUtil 9.7+ integration can be found here.

The UFO Extender program runs on the Windows version, providing a mouse-resizable window, a smoother-running, more responsive screen than DOSBox, and a host of fixes for various bugs or exploits in the game.. It also supports the use of higher-quality .mp3 music from the PlayStation release, and keyboard shortcuts. XcomUtil provides bug fixes, including for the disjointed-base bug, and additional ease-of-use features like the automatic re-equipping of soldiers before a mission and appending rank and stat info to soldier names.

Both also offer many gameplay modifications such as enhanced weaponry, different starting-base layouts, and randomized terrain and UFO layouts. These are all optional and turned off by default.

The programs are confirmed to run on Windows 7 as well as older operating systems, and with the Steam release.

XcomUtil supports the UFOExtender launcher, but assumes the use of DOS or DOSBox at several points in the installation process, so specific steps are required to run them simultaneously:

  1. Install X-COM. If installing from CD, make sure it is a full installation.
  2. Download the UFO Extender loader "", available at this Ufopaedia page, and extract it directly to the folder "XCOM", which is inside the base installation folder (e.g. "Xcom UFO Defense") in distributions with DOSBox.
  3. In the "XCOM" folder open UFOExtender.ini, find "D3D=0" and change it to "D3D=1" and change the value of "D3D Windowed" from 0 to 1. Save and close the modified .ini file.
    • On Windows 7 and Vista, you'll only be able to run this mod combo in a window. It will launch work once in fullscreen, and not again subsequently (The window can be maximized though).[citation needed]
    • If you do not wish to install XcomUtil as well, stop here, and you may run the game by launching "UFOLoader.exe" in the "XCOM" folder.
  4. Download the XcomUtil install file, currently "XcomUtil 9.7 Beta-442.exe", available at the downloads page at Run this file, again directly selecting the "XCOM" folder as the install location. If unavailable, use this .zip file for build 442, extract it into the XCOM folder, and then run XcuSetup.bat.
  5. XcomUtil setup should now be running in a cmd.exe window. If the cmd.exe screen appears blank, right-click on its title bar and select Properties. Under the Colors tab set "Screen Text" to a contrasting color from "Screen Background".
  6. When asked if you wish to configure XcomUtil now, enter "yes" and allow the program to run.
    • XcomUtil setup may also ask Steam users if they wish to use XcomUtil when X-COM is launched from Steam. However, launching from within Steam will still launch DOSBox instead of the UFO Extender launcher, so select "no". You cannot launch with UFO Extender from Steam's menu.
  7. On the screen that says "Windows 7/Vista has Issues displaying DOS/Win. On startup you get a blank screen..." enter "no" to decline installing the patch suggested.
  8. Enter "yes" when asked if you wish to enable the use of UFO Extender when you launch the game.
  9. Continue answering the rest of the prompts with the options you prefer. If you do not wish to change gameplay, you can still enable the re-equipping of soldiers before each battle with their last set of items, and the automatic addition of useful information to soldier name strings after battles. Info on all the options can be found in the "XcomUtil.txt" file in the "XComUtil" folder.
  10. If you want to change these options, run setup again by launching "XcuSetup.bat" in the "XCOM" folder. You can also do this after starting a game.
  11. You may now launch the game by running "RunXCom.bat" (not "XCOM.bat") in the "XCOM" folder.
    • If you are running Steam do not launch X-COM directly from its menu.
    • Do not run the file "xcomutil.exe" to launch the game. It will not work outside DOS or DOSBox. Xcomutil.exe simply provides a launch menu, with options for running the Xcomutil setup and the X-COM sound programs.
  12. Set additional UFO Extender options as you see fit by altering UFOextender.ini with Notepad. Information can be found here. In the provided download, all options are off by default, including enhancements that do not affect gameplay. You may enable Geoscape and Battlescape keyboard shortcuts and the stat display on the equip screen by setting the appropriate "Apply" values from 0 to 1, and set the keyboard shortcuts.
  13. To use the enhanced music from the PlayStation version of the game, download the appropriate .mp3 files found here (right-click and select to save the links). Place them together in a new folder inside your XCOM folder. Name the new folder "mp3". Open "UFOExtender.ini" with Notepad and under the "Music" heading set "Apply" from 0 to 1. Set the track names to match those in the new mp3 folder. The .ini file should appear similar to the excerpt below. The PlayStation files include additional Geoscape music; you may choose to set up different tracks:
UFOExtender.ini suggested music settings
;Source=PSX CD

CD Drive=F

MP3 Folder=mp3
Battlescape=X-COM UFO Defense PSX - 10 - Battlescape1.mp3
Start Menu=X-COM UFO Defense PSX - 09 - Final Briefing.mp3
Bad Ending=X-COM UFO Defense PSX - 09 - Final Briefing.mp3
Good Ending=X-COM UFO Defense PSX - 12 - Mission Accomplished.mp3
Geoscape=X-COM UFO Defense PSX - 01 - Geoscape1.mp3
Dogfight=X-COM UFO Defense PSX - 08 - Dogfight.mp3
Mission Debriefing=X-COM UFO Defense PSX - 07 - Debriefing.mp3
UFO Assault=X-COM UFO Defense PSX - 05 - Briefing1.mp3
Base Defense=X-COM UFO Defense PSX - 06 - Briefing2.mp3
Base Attack=X-COM UFO Defense PSX - 05 - Briefing1.mp3
Mars=X-COM UFO Defense PSX - 07 - Debriefing.mp3
Terror Mission=X-COM UFO Defense PSX - 06 - Briefing2.mp3


DOS/32A is a more advanced extender and open source replacement to DOS4GW. It can improve both performance and stability of X-COM.

It is recommended to turn off the extender's warning messages with its included ss.exe as they can be rather annoying and show up often when transitioning from geoscape to tactical mode.

Run in DOSBox

To improve DOSBox performance make the following changes to the DOSBox configuration file:

  • Change output=surface to output=opengl
  • Change memsize=16 to memsize=64
  • Change cycles=auto to cycles=auto limit 10000
  • Change prebuffer=20 to prebuffer=10

Enabling GUS music

UFOPedia has an excellent article on this here.

Game data

Configuration file(s) location

System Location
DOS <path-to-game>\sound\sound.cfg
Steam Play (Linux) <Steam-folder>/steamapps/compatdata/7760/pfx/[Note 1]
XcomUtil stores it's config info inside a file called xcomutil.cfg
UFO Extender stores it's config info inside a file called UFOExtender.ini
OpenXcom stores data in %USERPROFILE%\Documents\OpenXcom\ on Windows and $XDG_DATA_HOME/openxcom/data on Linux.

Save game data location

System Location
Steam Play (Linux) <Steam-folder>/steamapps/compatdata/7760/pfx/[Note 1]
missdat\ folder stores temporary data related to current active save game.

Save game cloud syncing

System Native Notes
GOG Galaxy
Steam Cloud


OpenXcom in-game video settings.
OpenXcom in-game video settings.

Graphics feature State Notes
Widescreen resolution
Use OpenXcom. Click on the resolution box to input the resolution.
4K Ultra HD
Field of view (FOV)
Toggle with Alt+ Enter when using DOSBox. Hackable on CE with UFO Extender. Native with OpenXcom.
Borderless fullscreen windowed
Natively included in OpenXcom.
Anisotropic filtering (AF)
Anti-aliasing (AA)
Vertical sync (Vsync)
Use OpenXcom. A frame rate cap can be set in the Advanced menu.
60 FPS
120+ FPS
Use OpenXcom.
High dynamic range display (HDR)
See the glossary page for potential alternatives.


Every key is by default already mapped when using OpenXcom.
OpenXcom in-game input settings.
OpenXcom in-game input settings.

Keyboard and mouse State Notes
Use OpenXcom.
Mouse acceleration
Use OpenXcom. Values can be set through the Scroll Speed option.
Mouse sensitivity
Mouse input in menus
OpenXcom also implements mouse wheel support.
Mouse Y-axis inversion
In the Advanced menu, under Geoscape.
Controller support
For DOSBox use the DOSBox Mapper (see the glossary page for other workarounds).


OpenXcom in-game audio settings.
OpenXcom in-game audio settings.

Audio feature State Notes
Separate volume controls
Use OpenXcom.
Surround sound
Use OpenXcom.
Closed captions
Mute on focus lost
For DOSBox change the priority background value in the DOSBox configuration file.
Royalty free audio
Red Book CD audio
PS1 port only. Tracks can be hacked in on CE with UFO Extender.
General MIDI audio
Use keyboard plus and minus (+ and -) to adjust music volume in DOS version.


The original release only shipped with the English language.
Language UI Audio Sub Notes
A patch to add US style spelling (verses UK) is available here.
Use the Italian Language patch. Replaces French.
Use the Spanish Translation patch.
1) Use the OpenXcom.
2) Fan translation by «» for original, download


Multiplayer types

Type Native Players Notes
Local play
2 Versus
Hotseat. Requires XcomUtil; a tutorial explaining the process can be found here. A batch to simplify the process can also be found here (direct link).
LAN play
2 Versus
Use the above method, but also requires passing save files around between computers (physical media or email, ect). Alternatively use the UFO 2000 Mod (Windows only).
Online play
2 Versus
See note above.

Issues fixed

Almost every single major bug has been fixed in OpenXcom.

Difficulty bug

The original DOS version of the game has a bug that would cause the game to play at the Beginner difficulty regardless of what the chosen difficulty. This bug went undetected until the Collector's Edition was released. The complaints regarding the game being too easy even at the highest difficulty setting led to the sequel's difficulty being scaled up so much that its easiest difficulty was harder than the intended hardest difficulty for this game. If using the DOS version, XcomUtil also patches this bug.

Game hang when attempting to use the MT-32 in version 1.4 (DOS)

Apparently certain 1.4 versions of the game shipped without an updated MT-32 driver causing the game to choke when attempting to load it. Use this patch and place it in the sound\ folder. Overwrite if necessary.

Other information


Technical specs Supported Notes
Hackable on CE with UFO Extender.
CE/Gold version only.
OpenXcom only.
DOS video modes VGA SVGA compatible.
ExecutablePPC 32-bit 64-bitARM Notes
macOS (OS X)
Requires OpenXcom. Downloadable builds were discontinued after July 2018.[4] An experimental PowerPC build was published in October 2020.[5]
Requires OpenXcom.[6]


Middleware Notes
Audio DIGPAK/MIDPAK CE instead uses dsound.

System requirements

Minimum Recommended
Operating system (OS) 5.0
Processor (CPU) Intel 386 20+ MHz
System memory (RAM) 2 MB
Hard disk drive (HDD) 10 MB
Video card (GPU) VGA


  1. 1.0 1.1 File/folder structure within this directory reflects the path(s) listed for Windows and/or Steam game data (use Wine regedit to access Windows registry paths). Games with Steam Cloud support may store data in ~/.steam/steam/userdata/<user-id>/7760/ in addition to or instead of this directory. The app ID (7760) may differ in some cases. Treat backslashes as forward slashes. See the glossary page for details.