There are 16 users sharing this computer(!).

I get this quite often. Generally 3-5 users rather than 16.

I'd like to know:

(a) what it means (are they really human users or just programs running in background)

(b) how I can find out WHO they are rather than just knock them off every so often

(c) how I can figure out how they became users in the first place ... is this a security issue I need to be addressing?

Do you have about 16 devices sharing iTunes or your wirelss connection etc.? Maybe you also have a few users longged on to other accoutnts stup on your computer too.

Are you using that FAST-login feature? Or whatever it's called...

And no, I'm not talking about the auto-login.

Yep, I don't think I've seen this before installing the Security updates Java for OS X 2012-(001-003). Note, I did a little experiment and canceled the logout dialogue, then turned File Sharing off and then tried the logout. No more connected users.

Apple need to explain this.

Yep! I keep getting the same messages when I try to shut down It varies, though, how many users the pop-up window says are connected. Most often 3, but I have also had up to 8. Gets me worried too!

It seems to me that I started to get this message after I bought an ATV2. I enabled file sharing then (not SMB). Also I have an airport express + an iPod connected to the wifi network. I am running Lion on a MacBook.

And yes, Apple need to explain this. Please! 😕

Is your wireless router set up with a WPA2 Personal / password needed network? If it is not password protected, are your neighbors using (stealing) it?

This has absolutely nothing to do with Wireless networks. My config I have the Airport disabled and am on a 1Gbit wired network.

What's enabled in Sharing System prefs?

Are you using Fast User Switching?

babowa: yes, WPA2 password protected.

I have done some further investigations and it seems to be the file sharing that causes the multiple users in my case. I got the 3 users pop-up and then:

-Unplugged the incoming internet cable to the house --> still 3 users

-Shut down the ATV --> still 3 users

-Powered down the iPod --> still 3 users

-Disabled File Sharing --> the 3 user warning window disappeared!

When I use the <last> command in Terminal (it lists the last number of users on the system):

antons-MacBook:~ anton$ last -15

anton ttys000 Thu Apr 19 12:23 still logged in

anton console Thu Apr 19 12:04 still logged in

reboot ~ Thu Apr 19 12:03

shutdown ~ Thu Apr 19 12:03

anton ttys000 Thu Apr 19 00:36 - 00:37 (00:00)

anton ttys000 Wed Apr 18 23:12 - 00:35 (01:22)

anton ttys000 Wed Apr 18 10:14 - 10:14 (00:00)

anton console Wed Apr 18 00:03 - 14:03 (1+13:59)

reboot ~ Wed Apr 18 00:02

shutdown ~ Wed Apr 18 00:01

anton console Mon Apr 16 00:07 - 00:01 (1+23:54)

reboot ~ Mon Apr 16 00:05

anton console Sun Apr 15 23:53 - 00:05 (00:12)

reboot ~ Sun Apr 15 23:51

reboot ~ Sun Apr 15 22:50

which gives no other users than myself - login via keyboard - so it seems the 3 users must be some kind of internal system users, caused by the filesharing and the interaction with the ATV and iPod somehow?

Well that's the closest I come to an explanation - it seems to be harmless.. although the high number of users that Dwerf have seen (mee too) still puzzles me..?

I do still find it odd that OS X doesn't appear to at least allow administrators to find out WHICH users are logged on (A message like "There are 3 users sharing this computer (johnsmith, console, hacker)" would be so much more helpful! After all, the system itself must know which users are logged on.

In fact, I'm just going to suggest this to Apple now...!

I agree! I wonder what it will take to get an Apple Support person to comment in this thread? Do we all have to buy extra-extra support services? 😕

TheKnowledgeSeeker002 wrote:

I do still find it odd that OS X doesn't appear to at least allow administrators to find out WHICH users are logged on (A message like "There are 3 users sharing this computer (johnsmith, console, hacker)" would be so much more helpful! After all, the system itself must know which users are logged on.

In fact, I'm just going to suggest this to Apple now...!

Good idea. I have never seen this in all my years with Mac, only when somebody in range logs onto my network (obviously after I have given them permission and the password) and then it will come up as 1 user is sharing your computer network.

Anyway good luck

Pete

I wonder what it will take to get an Apple Support person to comment in this thread?

A lot. Apple doesn't respond on these forums because they are intended to be a user to user interface (people like you responding to people like you). You can contact Apple via the contact links but they usually do not respond. You can try calling technical support (I don't know if they will charge you for the service).

Limnos wrote:

I wonder what it will take to get an Apple Support person to comment in this thread?

A lot. Apple doesn't respond on these forums because they are intended to be a user to user interface (people like you responding to people like you). You can contact Apple via the contact links but they usually do not respond. You can try calling technical support (I don't know if they will charge you for the service).

Yes, what I suspected. My Apple Support scheme expired some time ago, and I didn't really see the point in renewing it. Not even to get an answer to this.. 😝 Maybe someone more clever than me will read this thread and solve the mystery!

so it seems the 3 users must be some kind of internal system users, caused by the filesharing and the interaction with the ATV and iPod somehow?

This would make sense. I use a much older system (10.4.11) and in Activity Monitor I can see listed as users: my userID, "root", "windowserve", and "nobody" (yes, "nobody"). I remember a few years back doing something that showed me a much longer list of "users" that were all kinds of services running on my computer.