Can’t edit anymore, but I’ve found the issue : Steam appmanifest file pointing to a non existing folder.
So I tried updating to Game Hub 1.0, then at launch it gave me an error saying there was an illegal character in the path.
I looked in the logs and it happened during Steam file scanning.
With Process Monitor I could identify which was the last appmanifest file read, it was about “Special K” a tool to inject 3D settings stuff in games.
I deleted this file and tried again, now I got another error about a null value.
I then updated to Game Hub 1.6.4, and it worked !
Now both lists populates (installed and compatible games).
So if you plan to update Game Hub, add checks upon launch to scan folders only if they are defined in the appmanifests files and only if they exist, to avoid this kind of error I was getting.