When a Steam game won't launch, the first thing to do is restart your computer and then run Verify integrity of game files on that game from your Library, followed by Windows and graphics driver updates. Steam Support describes a game that seems not to launch as usually one that crashes right after starting, for a variety of reasons, and says many cases can be solved yourself. This guide covers only launch failures; for capturing gameplay see how to record Steam games. Menu paths follow the Steam Support pages as checked on September 30, 2026.
Symptoms, causes, and first actions (per Steam Support)
| Symptom or error message | Cause described in the official docs | What to do first |
|---|---|---|
| Game flashes open then closes, or seems not to launch at all | Usually a crash right after launch, for varied reasons. Corrupted files, outdated Windows or drivers, interfering software, and low specs are the items to check. | After a restart: Verify integrity of game files, update Windows and drivers, disable non-essential software, compare against the store page requirements. |
| Failed to start game (app already running) | Most common with games that silently crashed or otherwise did not run properly. It can also mean the game is already running under another Windows user account. | Verify integrity, End Process for the game in Task Manager, leave the Steam beta, log out other user accounts and restart. |
| Failed to Start Game (Missing Executable) | Game files are missing or blocked by another program. The most common cause is antivirus wrongly flagging a game file as malicious and quarantining it. | Mark the reported file as safe in your antivirus, set the antivirus to Game Mode, or exclude the game folder from scans. If it is not antivirus, restart and verify integrity. |
| An error occurred while updating [game title] or installing [game title] | This is an update or install error rather than a launch error, and has its own page (Update & Installation Issues). | Outside this guide. Check that page's basics such as restarting, Clear Cache, and Repair Folder. |
| The Steam client itself won't open or crashes | A client problem rather than a game problem, covered by the Steam Client Troubleshooting page. | Restart the computer and Steam, and reinstall Steam in the same location if needed. The docs say to reinstall to the same location and warn that uninstalling Steam by any other method deletes all game and user data. |
| PC matches or falls below the store's minimum specs | A device that exactly meets or falls below the requirements may not run the game, and even close to the requirements can cause performance or launch problems. | Compare the System Requirements section of the game's store page with your PC. |
First decide whether it is a launch failure
This guide covers only games that won't start or that close right after starting. Steam Support says to begin the checks from a freshly restarted computer, and this guide puts the file-corruption check first. If the screen shows Failed to start game (app already running) or Failed to Start Game (Missing Executable), go straight to that row in the table above. Install and update errors, and problems with the Steam client itself, have their own Steam Support pages, so the table separates them out. If the game starts fine but crashes mid-session only while recording, that is a different problem covered in why a game crashes while recording.
Order of checks when a game won't start
- 1Restart the computer — Steam Support says to follow the remaining checks after a fresh restart of the computer. Restart Windows itself rather than only closing Steam, then open Steam again. The integrity-check page also starts with a restart.
- 2Run Verify integrity of game files — In your Library, right-click the game, or click the gear icon at the far right of the game's Library page, and choose Properties.... On the Installed Files tab, click Verify integrity of game files. It can take several minutes, and the docs say that seeing some files reported as failed is normal for most Steam games.
- 3Update Windows and .NET Framework — As the docs put it, search for update from Start and run Check for Updates. Steam Support says to fully update Windows, and notes that Microsoft .NET Framework also arrives through Windows Update and that AMD Radeon drivers and some games require it to be installed and current.
- 4Check and update the graphics driver — Press Windows Key + R, type dxdiag, and click OK, choosing Yes if a driver signature prompt appears. On the Display tab, read the Device area (Name, Manufacturer, Chip Type) and the Drivers area (Version, Date), then click Exit. Then download the latest driver from the official page of your graphics card maker: NVIDIA, AMD, or Intel. The docs explain that outdated drivers can hurt performance even when the hardware meets the requirements.
- 5Turn off software that can interfere — The Programs Which May Interfere with Steam page lists anti-virus, VPN, anti-spyware, firewalls and security applications, P2P and file sharing software, FTP and web server applications, IP filtering or blocking programs, and download accelerators or managers. Close or disable the program, exit Steam, and start it again; some cases need a system reboot. The page also says it is always a good idea to work with a specialist to check how these applications are set up. Steam does not provide per-antivirus instructions, so use your antivirus vendor's support pages. Installation files an antivirus deleted or damaged can be restored with Verify integrity of game files.
- 6End a stuck game process — This applies to the app already running error. Press Ctrl+Shift+Esc to open Task Manager, select the game's executable on the Processes tab, right-click it, choose End Process, and confirm with End Process again. If that fails, restart the computer. If you are in a Steam beta, go to Steam at top left, then Settings, then the Interface tab, set Client Beta Participation to No beta chosen, and click Restart Now. Also log out of other user accounts, since the game may be running there, and restart.
- 7Compare with the store's system requirements — On the game's Steam store page, compare the Minimum entry under System Requirements with your PC. Steam Support says a device that exactly meets or falls below the requirements may not run the game, and that being near the requirements can still cause problems.
Checklist before you contact support
- Did you restart the computer and then reopen Steam?
- Did you run Verify integrity of game files to the end? Failed files that are local configuration files can be ignored.
- Are Windows and your graphics driver fully up to date?
- Did you turn off interfering software such as antivirus, VPN, or firewalls, or exclude the game folder from antivirus scans?
- Do you have an uncropped screenshot of the error? A Steam Support ticket needs an uncropped screenshot, a System Report, and the list of programs you removed.
- Did you select the game in your Library and check the Support tab above Activity for the developer's contact options?
If a recording app was running
Steam Support's Update & Installation Issues page names recording software directly as an example of software that can cause problems while downloading or running games, and the Steam Client Troubleshooting page also lists recording software among the programs to check. So if a game only fails to start while a recorder is open, fully closing the recorder and launching the same game is the simplest way to split the cause. DOR is a free Windows app: once a supported game is running, it recognizes the game on its own and saves the full match as an mp4 file. Counter-Strike is one of the games that gets full-match auto recording plus automatic highlight clips for kills and similar moments. On an NVIDIA graphics card DOR encodes with NVENC by default, so for the comparison just relaunch the same game once with DOR closed and once with it open. That does not mean DOR causes or fixes the launch errors in this guide. If the game starts but frames drop once recording is on, see fixing FPS drops while recording games.
Official pages checked
Checked on September 30, 2026. This guide follows Steam Support: Games do not run after 'Preparing to Launch' for games that do not run after Preparing to Launch, Verify Integrity of Game Files for the check procedure, and Failed to start game (app already running) for that error. The Missing Executable, Programs Which May Interfere with Steam, Update & Installation Issues, System Reports, and Updating drivers pages are on the same help.steampowered.com site. Menu names are kept in English because the Steam Support pages showed English text even in other language settings. Steam updates can change menu paths, an individual PC configuration may need a local technician, and game-specific error codes and anti-cheat problems belong with the game developer's support.
