Screen sharing to multiple macs ARD 3.8

"However the screens on the target computers show only black . . . can someone confirm this is also what you get?"

It's definitely not what you're supposed to get. I've screen shared the admin workstation as well as client workstations to one, a number or all of the workstations in defined computer lists.

Either you're trying to this over multiple subnets/VLANs and there's something on your network blocking the protocol or you've not enabled all of the options in remote management on the client workstations.

"Any ides for a fix?"

Two things you could try is using the kickstart command to restart ARDAgent or removing all of the workstations from your All Computers list and adding them again. I would try the second option first.

Some questions: Has this ever worked? If it did when did it stop? When it stopped was there anything that you're aware of, or can recall, that happened on your network (switches being changed, DNS/DHCP changes, data cabling upgrade etc, firewall/router changes etc, or with your client workstations (new build/deployment/upgrade/update etc) at roughly the time the feature stopped working?

Strange? What command(s) did you try? If you didn't know you need to run UNIX commands on target machines as root. The below always works for me:

/System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/ki ckstart -activate -configure -access -on -restart -agent

I doubt if there are blocked ports on target workstations if it's working for single workstations in turn? What I meant was if there's something on your network blocking, or not able to support this type of network traffic. Some more information regarding the network environment you're in might help us further to help you? For example what subnets are in use etc. It's possible the way the workstations were built/deployed has 'caused' the problem? Any information regarding his may also help. Beyond this and short of being there it's difficult to help further. All I can say is in my experience this always works in the way it's meant to and whenever I've seen the problem you describe it's invariably network or system related. However to test for blocked ports on the target workstations find the IP addresses of the workstations you want to control (easily done using ARD) and issue this command:

telnet xxx.xxx.xxx.xxx 5900

Where xxx.xxx.xxx.xxx is the IP address of the target workstation. The management/control port is 3283 which I would also test in the same way. If you get a response from the 5900 port but not the 3283 port then you've not enabled all the remote management options in the sharing preferences pane.

Apologies it's a typo. No space between ki ckstart.

Your deployment method is not one I would choose as it makes every single mac the same in every respect. Basically you're not allowing for ByHost settings, - amongst other things - unique to each mac. All your macs should be different in terms of themselves but have the same consistent OS, software and configuration. Cloning using disk utility is not really a deployment solution/method. DeployStudio or even Apple's own NetInstall/NetRestore would be the way to do this for multiple macs in a networked and managed environment such as yours. If you've less than five then I would do them manually and individually. I would not use Time Machine either for the same reasons.

To answer your question, yes, using Disk Utility in this way may well be the reason why it's never worked and possibly never will.

As for Wi-Fi it should work but it depends on the 'quality' and coverage of your WAPs. As a simple test try it wired to see if that changes anything. TBH if you've a wired gigabit network that can accommodate all your workstations I would always use that instead. These are desktops after all and not likely to move anywhere easily in the same way laptops would.

No, you're not screwed and there's no need to do a restore.

I use the following script that 'sys-preps' a mac ready for deployment. You can use it if you like (at your own risk) but obviously change it to suit on the workstation you're going to use as your deployment model. Apple calls this the 'Golden Mac'.

I'm assuming the following:

1. The local administrator account's short name is localadmin (change this to suit). NB if it was me I would make sure there is only one local admin account.

2. There are no student accounts or there home folders stored locally. My assumption is they're all logging in over the network (ie: Open Directory)

3. Printer(s) are configured as you want them.

4. All the software/apps you want the students to use are already installed.

5. Everything, including the OS, any other Apple updates as well as 3rd-Party apps or software etc is up to date.

6. If the macs are up to date then as a just in case, download the full combo update for the OS version you're on and install on that one workstation.

You only need to do this on one mac. You can run what follows (simply copy/paste) in ARD's Send UNIX Command window.

rm -R /var/db/BootCache.playlist

rm -R /var/db/volinfo.database

rm -R /var/vm/*

rm -R /var/vm/sleepimage

rm -R /System/Library/Extensions.kextcache

rm -R /System/Library/Extensions.mkext

rm -R /System/Library/Caches/*

rm -R /Library/Caches/*

rm -R /Users/localadmin/Library/Preferences/ByHost/*

rm -R /Users/localadmin/Library/Caches/*

rm -R /Users/localadmin/Library/Saved\ Application\ State/*

rm -R /Users/localadmin/Library/Preferences/com.apple.recentitems.plist

rm -R /Library/Preferences/SystemConfiguration/*

rm -R /Library/Managed\ Preferences/*

rm -R /Library/Preferences/OpenDirectory/*

diskutil repairPermissions /Volumes/Macintosh\ HD

reboot h now

You can miss out the the last reboot command if you wish as a simple manual restart will do the same thing. However, remember the first golden rule of IT: "If you can do it sitting on your a@*e then do it as it's better than walking." Don't worry if some of the commands return an error. These will be harmless as some of the folders/files won't be there. Remember to send it as Root!

So what does the script do?

Basically it 'resets' the mac back to a state where it's nameless (there's no name in the Sharing Preferences Pane) as well as removing any cached data and settings specific to that machine and users(s). It also removes any bindings you may have to either Open Directory and/or Active Directory and locally cached managed preferences applied by WorkGroup Manager. Finally it repairs permissions for the drive.

Once done and assuming you're using OS X Server's NetBoot Service and Deploy Studio to first; capture the image and second; deploy it to the rest. You can use Deploy Studio's powerful workflow interface to give all the workstations a unique name, set the date and time server for SSO authentication as well as binding/joining Active and/or Open Directory.

But before you capture the image and after you've ran the series of 'sys-prep' commands I would prepare another workstation in the same way. Then login to the prepared workstations. Enable Remote Management - remember to tick all the options - and try sharing your screen with the two of them. Hopefully that may 'cure' the problem?

How many other local user accounts are there and are they standard (ie: non-admin) accounts?

Ideally you should use a deployment system as already mentioned but you can use Disk Utility as long as you shut down the workstation you're preparing first and then target disk mode it to another mac. Use DU on that mac to create a restore disk image.

Make sure you use the Scan Image for Restore feature under DU's Images menu after you created the restore disk image and before you restore it. Do this for two of your workstations first. After restore log in as the local admin, name the macs using whatever naming convention you want and make sure you've enabled Remote Management with all the options enabled.

Before you test the screen sharing with those two macs, make sure you remove the two macs you've just restored from the All Computers list. Scan and add them again. Hopefully screen sharing to multiple workstations should now work. If you continue and do the rest and it's working as you want then get back to me and I'll give you a set of other commands that should hopefully make your life (and your students lives) easier in terms of administration, monitoring and usage.

Yes issue the commands for the other local user as well.