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Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →The fix for a Dawn of War window or fullscreen problem depends on which edition you own and what the game actually does when it starts. The classic Anniversary Edition and the Definitive Edition are handled differently, so identify your version first, then match your symptom to the steps below.
Identify which Dawn of War you are running
“Dawn of War” refers to two separate PC releases on Steam, and advice for one does not transfer cleanly to the other. Check the title shown in your Steam Library before you change any files.
| Release | Steam details used for this article | Fullscreen guidance that applies |
|---|---|---|
| Dawn of War, classic Anniversary Edition | Relic Entertainment strategy game; Steam lists a release date of January 1, 2006 | A community-reported Local.ini edit, general Steam launch options, and one anecdotal tool (see the classic section) |
| Warhammer 40,000: Dawn of War Definitive Edition | Steam lists a release date of August 14, 2025, with a separate Windows 10 64-bit minimum specification | Window-behavior changes in patch 2.7.0, dated February 17, 2026, plus the official support route for persistent issues |
Match your symptom before you change anything
Fullscreen, windowed mode, resolution, and black bars are related but separate problems. Use the symptom that most closely matches what you see:
- The game will not switch between fullscreen and windowed: start with the classic
Local.iniedit or a Steam launch option for classic releases. For the Definitive Edition, update first and then check the patch 2.7.0 section. - The game opens in a small window: this is the case most launch options target, since
-fullscreenis documented to force fullscreen startup. - Wrong resolution: the Steam options
-wand-hset a width and height, but support for them in this game is not confirmed (see below). - Black bars: the sources reviewed do not document a Dawn of War-specific aspect-ratio setting, so none of the steps here are guaranteed to remove them. Check your monitor’s own scaling options and your Windows display settings, and treat any change there as separate from the game’s configuration.
- Crash or failure at first launch: the Definitive Edition patch 2.7.0 notes describe a fix for a first-boot crash caused by a display device that was not detected correctly. Update before troubleshooting further.
Classic Anniversary Edition
For the classic Dawn of War 1 games, there are three approaches, listed from most to least supported. Only the first has a specific written recommendation behind it, and even that comes from a community forum rather than from Relic or Steam.
#1 Best Overall
- Real-time strategy game based on the popular table-top war game
- Vie for the survival of mankind or its ultimate destruction
- Control 1 of 4 unique races
- Improved resource model makes it easier to focus on frontline action
- Single player campaigns; Multiplayer for up to 8 via LAN or Internet
Edit screenwindowed in Local.ini
A Steam Community reply from 2018, in a thread titled “Changing from windowed to fullscreen?”, recommends changing a single setting in Local.ini. The reply’s author says the setting works across the Dawn of War 1 games, and the original poster reported that it fixed their situation. It is user-reported guidance, not an official instruction.
- Close Dawn of War completely, including any launcher window.
- In Steam, open your Library, right-click the game, choose Manage, then Browse local files. This opens the installation directory.
- Before editing anything, copy
Local.inito a safe location, such as a folder outside the game directory namedLocal.ini.bak. This copy is your way back to the original values. - Open
Local.iniin a plain text editor such as Notepad. - Find the line beginning with
screenwindowed. Set it to0for fullscreen or1for windowed mode. - Save the file without changing its name or extension, then launch the game and check the result.
To undo the change, close the game and copy your backup over the edited file. If the screenwindowed line is missing from your copy, do not add one by guessing a value. Restore the backup and try a launch option instead.
Use Steam launch options
Steam’s general launch-option documentation, published by Steam Support, states: “-fullscreen – Forces the engine to start in fullscreen mode.” It also documents -windowed or -sw for windowed mode, and -w [width] and -h [height] for resolution. This is general documentation for Steam launch options, not a guarantee that Dawn of War honors every switch.
- In Steam, open your Library, right-click the game, and choose Properties.
- On the General tab, find the Launch Options field.
- Enter one option, for example
-fullscreen, or-windowedto test windowed mode. - Start the game and check whether the mode changed.
Test one option at a time. If the game behaves worse, clear the field completely. Resolution switches follow the same pattern and must use numbers your monitor supports, for example -w 1920 -h 1080 on a 1920 by 1080 display. If the game ignores the values, return the field to its previous state.
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Rank #3
- Put new units for the Space Marines, Ork, Eldar, and Tyranid armies and two new last stand heroes to work for you on the battlefield.
- This expansion allows you to continue your fight against the enemies of the Emperor and use your squads’ wargear, abilities, and experience to battle Chaos in 15 new missions.
- New ice planet graphics set increases visual diversity and adds 7 new multiplayer maps while six-player online multiplayer and a raised level cap of 30 allows for even more glory and devastating abilities.
- New single player mechanic allows you to equip incredibly powerful equipment that corrupts your squad and will guide the story towards or away from the corrupting influence of Chaos.
- Swear loyalty to the Chaos Gods and play as the bloodthirsty Chaos Space Marines in multiplayer battles against both Chaos Rising and Dawn of War II owners.
GraphicsConfig.exe
A Steam Community report about the classic Anniversary Edition describes running GraphicsConfig.exe, which forced windowed startup for one user. The author reported that the workaround helped only once and the problem then returned. Treat this as an anecdote, not a dependable fullscreen fix.
Definitive Edition: what patch 2.7.0 changed
The patch 2.7.0 notes, dated February 17, 2026, describe two display-related changes. They report a fix for a first-boot crash that occurred when the display device was not detected correctly. They also state that manual window resizing in windowed mode was disabled, to prevent a mismatch between the game resolution and the window resolution.
Rank #4
- Real-time strategy game based on the popular table-top war game
- Vie for the survival of mankind or its ultimate destruction
- Control 1 of 5 unique races
- Improved resource model makes it easier to focus on frontline action
- Single player campaigns; Multiplayer for up to 8 via LAN or Internet
The second change matters if you were resizing the window by dragging its edges to fit your screen. That no longer works on the patched version, so use the fullscreen or windowed options the game provides instead. The notes establish that display and window behavior changed, but they do not claim that every fullscreen problem is resolved.
- Update Dawn of War Definitive Edition through Steam and confirm the installed version is 2.7.0 or later.
- Launch the game once with no launch options or manual window changes, and note whether the symptom persists.
- If it does, record your setup before reporting it. Include the number of monitors, which one is primary, the resolution and scaling shown in Windows Display Settings, your Windows version, the exact symptom, and any Steam launch options or edited files.
- Report the issue through the official support route named in the patch notes, attaching the details above.
When none of the steps work
The available evidence does not identify your operating system, monitor arrangement, or exact symptom, so no single fix can be promised. Before you try a further workaround, check the following:
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Best Value
- New features of the expansion include: 15 new missions, new units for all factions, moral based corruption mechanic and the new playable multiplayer faction, the Chaos Space Marines.
- Contains both Warhammer 40,000 Dawn of War II and its expansion pack Warhammer 40000: Dawn of War II: Chaos Rising.
- Classic real-time strategy gameplay that focuses on the need for strategy in the absence of endless reinforcements and resources.
- Simplified entry point into games allows both veterans of RTS gameplay and newbies to get into the action quickly and easily while learning the game at their own pace.
- Online multiplayer allowing you to play through both the single player campaigns included cooperatively with a friend, or go it alone as any of the five factions against online competition.
- Which edition is installed, as shown in your Steam Library.
- Whether the game was updated to the current version through Steam.
- Whether
Local.inihas been edited, and whether a backup exists. - Whether any Steam launch options are set, and whether they are the only ones.
- Whether the problem is a mode switch, a window size, a resolution, or a crash at startup.
Changing one setting at a time, and keeping a record of each change, makes it much easier to tell which step affected the result.
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