I have just read a similar post and I'm mesmerised if this is a permanent problem.
I cannot load the steam exe on my pc. When I switched the PC on this evening I got a message saying Avast has updated.
Then I went to load up Football Manager 2020 but I get the following error message:
steam://rungameid/1100600
Windows cannot find steam 'steam://rungameid/1100600'. Make sure you've typed the name correctly, then try again.
The exe is there. I can see it. I've tried to run as adminstrator, I've downloaded Malwarebytes, I've checked that Steam is enabled from Wake Up mode. I don't know what to do.
I have undone the broken registry files that were done 2 days ago. With that in mind though the game worked fine yesterday.
Has my Avast Cleanup Premium done something irrepairable to my Steam files. Please can anyone help me.