Task Manager - Processes & Users Tab empty
Solution 1:
I see that you are an italian like me and I also had this exact problem.
In the end I found that the problem was a program needed for the CNS (Tessera Sanitaria), in particular the one called IDProtect (it's only for the ACTALIS type of CNS, see this link for more information).
Remember to close the task manager, shutdown the program and then reopen the task manager to see the changes.