Once Human not launching is an annoying issue that may be due to various reasons.
This post fromMiniToolintroduces some useful and easy solutions to help you remove it.
Now, keep on your reading.

Once Human is a post-apocalyptic open-world survival game.
if you bump into these issues, follow the troubleshooting steps below to deal with the issue.
Here is how to do that:
1.

Right-click Once Human in Steam Library and chooseManage > Browse local filesto launch the game installation folder.
Locate the games executable file and chooseRun as administrator.
Here is how to do that:
1.
TypeDevice Managerin theSearchbox to open it.
Expand theDisplay adapterscategory and find the graphics driver.
Then right-click it to choose theUpdate driveroption.
After that, it’s possible for you to choose theSearch automatically for driversoption.
If there is a newer update, it will be downloaded and installed automatically.
To fix the Once Human not launching issue, you had better end the background process on your system.
Press theCtrl + Shift + Esckeys to openTask Manager.
Go to theProcessestab and choose the task you want to close individually.
Then, clickEnd Taskto close it.
Therefore, if you use third-party overlays, you had better disable them.
Here are the steps:
1.
Launch theSteamclient and go toLibrary.
SetOVERRIDE FOR Once HumantoDisable Steam Input.
Finally, you should restart the game to check for the issue.
As the DirectX 12 version is the latest one available for Windows, it may not support your system.
To turn it off:
1.
Go toSettings>Video.
Restart theOnce Humangame after applying changes.
Final Words
Now you know how to easily fix the Once Human not launching issue on Windows.
you could try the above solutions one by one until the issue gets fixed.
If all of these ways cannot work, hit up the game support for help.