Některé hry nemůžou být sdíleny, jako například GTA 4
Sdíleny také nemohou být hry na kterých je udělej VAC BAN

No, due to technical limitations, some Steam games may be unavailable for sharing. For example, titles that require an additional third-party key, account, or a subscription in order to play cannot be shared between accounts. Additionally, if you are VAC banned, you will be unable to share any VAC protected games.