Steam is quite a specific program because each game installed and downloaded through Steam needs Steam to be opened in order to run. This is obviously implemented for security reasons and because Steam is somewhat in charge of everything that happens in-game such as playing with your Steam friends, voice chat, and in-game microtransactions.
There are various reasons why Steam wants to control everything. One of them is definitely profit since Steam keeps a percentage of every sale which occurs such as purchasing a game or buying something in-game. The other reason is simple since it’s easier for users to use their Steam Wallet for all purchases rather than making an account for every single game.
One of the possible problems which can occur when you want to run a game through Steam is getting an error message saying “Failed to start the game (app already running). This problem occurs when your previous game failed to shut down properly or when you simply forgot to exit. However, this problem can sometimes be more difficult to fix, especially if you definitely closed the game properly upon finishing.
First of all, pay attention and check whether the game has finished closing yet. If you just exited a previous gaming session and you want to continue playing, the game might not have closed properly. This problem most commonly occurs if a high-end game has been opened on a low to mid-end computer and it takes a lot of time for the game to close properly.
The first thing you should do is to try opening Windows Task Manager by clicking the combination CTRL + ALT + DEL or CTRL + SHIFT + ESC. When the Task Manager opens, browse the running processes and check whether a process named similar to the game you are playing shows up. If it does, right click on the process and choose “End Process”. This should fix things immediately and you should be able to either close Steam or run another game.
TIP: Not all game processes are named exactly like the official game name since some Valve games operate under the process called hl2.exe since they have derived from Half-Life 2 and they are using the same Source engine. Some of these games include Team Fortress 2, Portal 2, and Counter-Strike 1.6. If you are not sure how your game process is named. Try opening its directory.
Even though Task Manager is sufficient in most cases, some users have reported that they needed to use additional software that displays more processes that are hidden by Task Manager. The best program to use is Process Explorer which can be found on Microsoft’s website as a free download. Process Explorer should provide you with a higher variety of processes and running apps so make sure you double-check processes with a similar or unknown name.
Finally, if you used some of the in-game features to open a third-party app such as a browser to visit one of the links, make sure you close everything before you proceed to close Steam or to open another game.