When I run Portal.bat, the CMD opens and then closes again. Then the Portal window opens and for no reason the left mouse button is spammed automatically. I already reinstalled Unpack several times. I have also completely reinstalled Steam but nothing Has helped....

Can you screen record a video where you try to run the batch file, then open the batch file in a text editor so we can see what code it's running? You can upload it to a short term video hosting platform like streamable and comment here, or you can send it in the #help channel in the discord https://discord.com/invite/gQ285vS

The same thing happens for me with HL1, although im not sure if its the same problem. try using TAB to navigate the menus? It might be tedious but if it works, it works.

I have been able to solve the problem. Somehow my wireless controller did not cooperate well with the USB input.So I pulled out the USB stick and now it works :D But anyway thanks for the help <3