UPDATE: Apple posted ARD 3.9.2 updaters in late March, which claim to have addressed most of the problems detailed in this post (specifically the keychain and offline issues).  Be warned though, there are a variety of stability issues that have been reported with ARD 3.9.2.

Apple released Apple Remote Desktop (ARD) 3.9 Client and Admin updaters on 2/21/17.  Based on the high number posts to different user forums reporting problems with these updates, I would advise not updating to ARD 3.9 until Apple released a subsequent update.

The bulk of the problems being reported about ARD 3.9 fall into one of these two categories:

  1. Can’t connect to Mac workstations after updating to ARD 3.9 Admin
    • Apple changed the behavior with ARD 3.9 Admin, where by default it can only connect to Mac workstations running ARD 3.9 Client. Apple also added a new preference setting in ARD 3.9 Admin, under the Security tab, for “Allow communication with older clients”.  This must be enabled to connect to Macs running older ARD 3.x Clients.
    • Even with updated ARD 3.9 Clients, or when the “Allow communication with older clients” setting is enabled, ARD 3.9 Admin may report ARD Clients as Offline or Access Denied. In some cases these Clients can be controlled or observed, but can’t be managed (i.e. send Unix commands or install packages).
    • There are a lot of workaround that have been posted on how to deal with this Offline/Access Denied issue, including creating a new local admin account on the Mac workstation then removing the client in ARD Admin and adding it back in with those credentials, but all of the workarounds are time consuming and don’t yield consistent results.
  2. Mac workstations display a password prompt: ARDAgent wants to use the “PrivateKeyStore-[#]” keychain
    • This happens on some Macs updated to ARD 3.9 Client, and occurs when ARD 3.9 Admin attempts to control or observe the Mac.
    • This prompt won’t accept any local password.
    • In most cases there is no way to dismiss this password prompt other than rebooting the Mac workstation or pushing out the ARD kickstart command via SSH.
    • Some people have reported that pressing the Cancel butting repeatedly will dismiss this password prompt, but others have reported that the prompt will eventually come back.

Other posted problems with ARD 3.9 include slow network scans, slow connection times, and slow redraw when controlling or observing.  Also of note: The ARD 3.9 Client and Admin updates require Mac OS 10.10 or later.