Why can't I add any more user? I have an Asus tablet with Lollipop on it.

Two week ago I was able to create another user on that device.
Now I want to edit another user but touching the lowermost bar does not start any action. (the text is greyed out, i don't know, if that was the case also two weeks ago)



I already contacted Asus support and they said, this feature had been removed by Anroid and they can't do anything.

I checked the build.prop and it does not contain a single entry for fw.xxx

Any idea, why I can't add another user?
You've reached the maximum numbers of users supported for your device. That's why the entry is grayed out. You can attempt to confirm this by executing the following command in a terminal emulator app or through adb:

pm get-max-users


If it shows Maximum supported users: 2 (Guest user is not included in maximum limit, so it doesn't matter whether it is setup or not; Primary user/Owner is included in the limit) then you know you hit the wall. The limit is set by the manufacturer.

Example for Nexus 6 running Android 5.0:

(Click an image to enlarge it)