This occurs when either you only have an integrated graphics chipset or when you have a computer using switchable graphics technology like e.g. nVidia Optimus.
To bypass it find:
and create a shortcut to witcher.exe. Right-click and open the shortcut’s Properties. In the Target textbox next to the path type: -dontForceMinReqs
(the path you chose)/System/witcher.exe" -dontForceMinReqs
(the path you chose)/System/witcher.exe -dontForceMinReqs
Make sure there is a space between the path and the -dontForceMinReqs parameter. Confirm with OK. Now you should be able to run the game from this shortcut.
1. Right-click on the game title under the Library in Steam and select Properties.
2. Under the General tab click the Set launch options… button.
3. Type -dontForceMinReqs and click OK.
4. Close the game’s Properties window and launch the game.
The side effect of using this switch is that texture quality setting won’t be usable anymore. Using this mod may help.