Sudden disappearance DoTA 2 from steam library

[who]

Hello, my steam tell me to install dota 2. I wonder why, because all I did was turn on my PC. I had a dota 2 game before i shutdown my PC, then, i close it. After that, i turn off my PC. I notice here, there is no dota 2 update when i'm going to turn my PC off, so i turn it off anyway. After a couple of hours, i turn on my pc, login with the same account, and here i am, find my dota 2 is missing. I checked my steamapps , and there is dota 2 files, completely. I checked library settings to check destination games, everything is find, but still, no dota 2.

I wonder why, any ideas ?
thanks :)
GL HF

*P.S : i have 5 games, but, only dota 2 is missing

[Chara the Explorer]

Go to the Dota 2 store page and try to install it again. More likely and not it'll notice the files and fix the issue.