I’ve noticed that, if you have a lot of games in an external hard drive, when you disconnect it, on reboot the games previously detected get cleaned and disappear from the list. It would be better if avast! remembered them even if the drive is disconnected.
No, when you reconnect the drive it can have another drive letter (applications on it will be seen as new ones).
See if this helps you:
http://www.addictivetips.com/windows-tips/assign-permanent-drive-letters-to-a-removable-usb-drive-in-windows/
Thank you for your response Eddy and Bob, but I already assigned a fixed drive letter to my drive, long time ago. It is always F:
But trust me, avast! forget the games if the drive is not connected after a reboot… Only one game persisted and it’s because is installed on C. The others… puff!!! 
Reported to Avast. Let’s see if that get us a reply and a resolve.
Thanks for the feedback. We indeed remove any games from the list of which the executables no longer exist (e.g. were uninstalled). This unfortunately includes this scenario of removing a drive full of games.
We’ll fix this behavior to detect whether it was the entire drive removed or just the game folder. You can expect it in a week or so.
Thank you!
I’m bumping this old thread just to check if things have been updated in regard to this issue. I cannot check it myself because I have uninstalled the component and don’t wont to play with avast! installation unless necessary. Better I ask here first. Anyone knows? @Hried?
Well, many things have changed since early 2017… 
Hi Asyn, know what? Eventually I tried it myself, and found out that nothing has changed, at least about my issue (confirmed to be a possible scenario by an avast dev). Probably I am, if not the only one, one of the few who keep games in an external drive. At this point I don’t think there will be “fixes”, if I can say so. Component uninstalled.
No problem, there are other solutions. Long time ago I already created a “Game Mode” feature via vbs and bat files, which disables with one click unnecessary programs and background processes, changes desktop background and runs a launcher bar just for games. I was interested in that particular feature that focuses the CPU priority on games… something that can be done with Task Manager… but having it enabled without touching anything would have been good. This is not my case, because I need an external hard drive for old good and brand new games.
P.S.: And please, do not consider the “built-in” gamemode windows 10 pretends to “offer” to the gamer… It just doesn’t work as expected with full screen games, and has conflicts with NVIDIA drivers… I already follow that route!
Hi, sorry, I’m no gamer. Feel free to wait for dev-input…