Do you actually HAVE notepad.exe in C:\folder\ location? That by why it spitting out that error, unless you have corrupted, or missing files, or drivers missing, or corrupted needing to run said app.

引用自 Dr.Shadowds 🐉：

Do you actually HAVE notepad.exe in C:\folder\ location? That by why it spitting out that error, unless you have corrupted, or missing files, or drivers missing, or corrupted needing to run said app.

It was an example. I can't add any exe to any game via that command anymore. It worked just fine few weeks ago.

I tested it out doing "C:\Windows\System32\notepad.exe" %command% it works just fine even try another app like emulator, and another game in steam, I tested using tap ninja as the game, and put command into that.

引用自 Dr.Shadowds 🐉：

I tested it out doing "C:\Windows\System32\notepad.exe" %command% it works just fine even try another app like emulator, and another game in steam, I tested using tap ninja as the game, and put command into that.

If you're on Steam Client Beta, C:\Windows\System32 has changed; previously it would redirect to C:\Windows\SysWOW64 due to 32-64 bit translation. If any shortcuts used C:\Windows\Sysnative to get around that redirection, they will have to be changed back to C:\Windows\System32 due to the Client now moving to 64-bit.

引用自 Dr.Shadowds 🐉：

I tested it out doing "C:\Windows\System32\notepad.exe" %command% it works just fine even try another app like emulator, and another game in steam, I tested using tap ninja as the game, and put command into that.

So, I tried adding

"‪C:\Program Files\NOTEPAD\notepad++.exe" %command%

To Deus Ex in my library and nothing changed. Same error.

Which Deus Ex you used? I want give this a shot see if I can get same error.

引用自 Dr.Shadowds 🐉：

Which Deus Ex you used? I want give this a shot see if I can get same error.

Doubt there's gonna be any difference, I got same error trying adding random exes to other games too.
It was Deus Ex Revision.

引用自 Crashed：

If you're on Steam Client Beta, C:\Windows\System32 has changed; previously it would redirect to C:\Windows\SysWOW64 due to 32-64 bit translation. If any shortcuts used C:\Windows\Sysnative to get around that redirection, they will have to be changed back to C:\Windows\System32 due to the Client now moving to 64-bit.

Did it on both standard, and beta, nothing changed.

引用自 Birmancat：

引用自 Dr.Shadowds 🐉：

Which Deus Ex you used? I want give this a shot see if I can get same error.

Doubt there's gonna be any difference, I got same error trying adding random exes to other games too.
It was Deus Ex Revision.

Yeah nothing changed for me, not sure for why it happening to you like that, best I can say try this.

Head to where steam installed, delete everything except for Steamapp & userdata folder, and steam.exe file, just move out userdata folder out of steam folder, now run Steam.exe see what happens when do this.

Note you may delete any customs you have done to steam like custom launch options, and custom artwork, or if you done anything like modding the client which likely deleted mod for client,

引用自 Dr.Shadowds 🐉：

Note you may delete any customs you have done to steam like custom launch options, and custom artwork, or if you done anything like modding the client which likely deleted mod for client,

I'd like to avoid that as much as possible. Is there a way to backup custom games with art etc?