Failed to Start Game (Missing Executable)

I see the error "Failed to Start Game (Missing Executable)" when launching a game through Steam. What can I do?

Troubleshooting

This error results from the improper delivery of necessary game files. Please follow the steps below to initiate a small download of the missing content:

Completely exit Steam.
Navigate to your Steam installation folder (~C:\Program Files\Steam)
Delete the 'appcache' folder.
Restart your computer and attempt to launch the game through Steam

If the issue persists, it may be that a program on your machine is interfering with the proper delivery of game files:

Please temporarily uninstall any applications listed in our Programs Which May Interfere with Steam.

Additionally, it is possible that anti-virus software is reporting game files as malicious.

Unsupported operating systems

Important:

Some titles can be downloaded through Steam on an operating system that they are not currently supported with. Check your game's system requirements on the title's Steam Store page or retail box. This is caused by the game's configuration as chosen by the title's developers. In cases such as this, even if a game can be installed, it will not run and is not supported on alternate operating systems in any way.

Running Steam as an Administrator

For Windows Vista, 7, and 8:

Completely exit Steam
Right-click on the shortcut which you use to launch Steam
Select "Run as Administrator."

For Windows XP:

Exit Steam completely.
Go to the "Start" menu, select "Run", type "regedit" and click "OK".
Navigate to the following registry key: HKEY_CURRENT_USER\SOFTWARE\VALVE
Right click and select "Permissions"
Check the "Allow" boxes for "Admin" and "System" for both "Full control" and "Read".

Flushing your Steam application files

You can reset the Steam application's files to rule out a few potential causes of this issue.

Exit Steam.
Open Internet Explorer, Safari or Firefox and type steam://flushconfig then press Enter. (If asked to allow this website to open a program, please click 'Allow' or 'OK')
When prompted by Steam to reset your configuration, please click 'OK' to confirm.
Once done, log in to Steam and re-test the issue.

If you have multiple installation folders for games doing this process will remove them. You will need to add the folders again in Steam so that your games will appear as installed.

In order to add the folders back to Steam, try the following:

Open Steam
Click Steam > Settings (Preferences on Mac)
Navigate to the 'Downloads' tab
Click the 'Steam Library Folders' button
Click on 'Add Library Folder' and add the directory that contains your games
Click 'OK'
Restart Steam

Verifying your game files

If you still encounter this issue after completing all of the troubleshooting steps listed above, please try verifying your game files. When verifying your game files, Steam may report that one or more filed have failed to verify. This is normal and the message can be safely ignored.

Submitting a Steam Support ticket

If you have completed all of the steps that are listed above and are still encountering this issue, please submit a ticket to Steam Support.

Ensure that you note which steps you have completed in your ticket. Additionally, make sure that you provide the following:

An uncropped screenshot of the error.
An MSinfo (PC) or System Profiler (Mac) report.
A list of the programs that you have removed per the Programs Which May Interfere with Steam article.

You may be instructed to perform operations that you have already completed in this article. If so, please complete them again as thoroughly as possible.

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