ARD and screen sharing become unresponsive when switching users

Not isolated. It just happened here too, also a headless unit. I tried ARD running on 10.6.1 connecting to 10.5.8, switched users and nothing. Have blue screen when I connected a monitor to the affected machine. The target is unresponsive to local keyboard input as well (was connected prior to the lost video event), not just remote access. After logging out (killall -u <2nd user>) ARD produces no window. Screen Sharing paints a black window with nothing in it. There appears to be a bug in the windowserver (?) process.

Mw

You are not alone. I also had exactly the same problem. Apple Remote Desktop control mode -> then switch to login window -> connection breaks, and it is impossible to start a new control/observe session. And the system.log show errors like kCGErrorIllegalArgument: CGSGetDisplayBounds

Same here. Headless Mac Mini running 10.6.1 Server.

Same log entry:

AppleVNCServer[64410] <Error>: kCGErrorIllegalArgument: CGSGetDisplayBounds (display b01a4668)

Ditto. Headless Mac Mini running 10.6.2. Same log entry.

When Screen Sharing and the remote user is switched, the Screen Sharing function fails. Can no longer connect without rebooting the remote computer.

Yes, it has lately become very difficult to use screen sharing on the Mac. If you log out one user you will never be able to log in again remotely.

If you change network location then authentication will not work and let you back in from the new place (maybe happens because I never leaved the session properly, but another machine cannot connect via screen sharing either on the same local LAN afterwards).

You have to be very careful not shifting between Ethernet and Airport as that will break any connection attempts even if on the same LAN (this might have been so before and for good reasons, perhaps).

Copying files over the Internet via ARD has never really worked in any situation (with some of odd exceptions).

Moving windows on the remote machine has for many years resulted in having them snapped to the edges of the remote desktop ... .

Basically you have to have the remote machine connected all the time to keyboard, mouse and screen and have someone standing in front of it as ARD cannot be relied upon these days.

I'm having a similar problem. My management computer is a MacBook Pro running 10.6.2 and ARD 3.3 (451.15). My remote server is a G5 tower running OS X Server 10.4.11. If I lock the remote screen (with the "curtains"), the remote server becomes totally unresponsive to ARD until a reboot.

Same problem here: Mac Mini Server 10.6.2 headless. When logging out or locking screen (switching user), Screen Sharing is gone.
Interestingly, I even can't login locally after attaching a display. It only shows an empty blue screen.

Seems as if the windows server hangs...

Same here on headless mini with 10.6.2 server. killall -9 WindowServer returns ARD functionality, but this is somewhat... bad resolution. All UI sessions are killed.

Exactly the same here...
At least, by killing WindowServer I'm able to login again...

But this has to be fixed...

I've posted a rdar://7505826 to Apple, you can track it from OpenRadar here: http://openradar.appspot.com/radar?id=136415

I'm having the same problem with a recent Aluminum iMac, using Snow Leopard. I switch users via the fast user switching menu and the other user logs in, but the screen stays with the previous user. In addition, when I log out the current user, I can no longer control the machine at all.

This occurs when controlling over the internet. I forward ports 5900 and 3283, which used to always work when controlling the previous iMac.

Here's the error I get once I disconnect and try to reconnect to ARD on the client Mac:

Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: kCGErrorIllegalArgument: CGSGetDisplayBounds (display 786550)
Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: setbackground error 268435459
Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: IOPMAssertionCreate error -536870199
Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: setbackground error to zero 268435459
Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: kCGErrorIllegalArgument: CGSGetDisplayBounds (display 786550)
Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: setbackground error 268435459
Jan 9 09:26:20 Aluminum-iMac AppleVNCServer[97396]: IOPMAssertionCreate error -536870199
Jan 9 09:26:21 Aluminum-iMac com.apple.launchd.peruser.501[99] (0x100207010.anonymous.SafariSyncClient[88002]): The following job tried to hijack the service "com.apple.Safari.SyncClient.IsRunning" from this job: com.apple.Safari
Jan 9 09:26:21 Aluminum-iMac com.apple.launchd.peruser.501[99] (com.apple.Safari[88004]): Exited with exit code: 1
Jan 9 09:26:21 Aluminum-iMac AppleVNCServer[97396]: setbackground error to zero 268435459

I currently can't recreate the problem of trying to switch users, since I can't log into the Mac remotely to test it.

I just had the same problem. ARD on my Leopard machine, managing Snow Leopard on a Mac mini. I turned the curtain on, and forgot to disable the curtain when I logged out of the user account. The curtain screen stayed up, and ARD got no response, so I had to reboot the Snow Leopard mini. Seems like this should have been fixed in the last ARD release.