Entire library giving me "invalid platform" error

[Fancyboy Ginswillington]

My entire steam library is bricked apparently. Every game is giving me the Invalid Platform error--games I have spent hours playing. Just 24 hours prior I was playing Elden Ring on this machine (a remote PC via Shadow) without issue, now I can't get anything to launch. Games launch on my laptop without issue.

So far I've tried...
Ending the Steam app process and restarting as Administrator
Clearing the Download Cache
Verify Integrity of Game Files
Repair Downloads Folder
Delete folders in the Steam Directory but Steam Apps, User Data, and one other (can't remember)
Uninstalling + Reinstall Steam, Redownloading of Games

Nothing has changed about my setup in the last 24 hours, and it's driving me up the wall trying to solve this. Any ideas?

[Fancyboy Ginswillington]

SOLVED: Uninstall/Reinstall of Steam + Downloading and Verifying the integrity of the game files did the trick. I don't know why every other solution thread I found didn't say this.

[Kyleth]

Thanks for the tip! Had the same problem today, using Shadow. Just tried this, all games work again after doing so :)

[wOOkymoo]

Thanks also for the tip, same issue today, also using shadow...

[Mr Affgot]

Is this a Steam or a Shadow problem? I too am using Shadow and everything was working just fine yesterday

[Cathulhu]

Shadow mucked something up.

[ragga]

I had the same issue as this today - I logged in without a sign in.. then clicke don a game (was Gwent in this case) and the login button was on there. clearly a BUG that's still not fixed

[Cathulhu]

Then contact support of Shadow. They mucked it up, they have to fix it.

[Wings]

I dont use shadow play that I'm aware of. this is totally ♥♥♥♥♥♥

[Wings]

Originally posted by Fancyboy Ginswillington:

SOLVED: Uninstall/Reinstall of Steam + Downloading and Verifying the integrity of the game files did the trick. I don't know why every other solution thread I found didn't say this.

I have hundreds of games so no not downloading them all again .

[kvbson]

Thanks for tips

[76561199181522831]

This thread was quite old before the recent post, so we're locking it to prevent confusion.