When you attempt to legacy remote control a machine after upgrading to 2017.3, you may see the following error:
"Authentication failed because a certificate was not found on the remote computer".
We changed the Remote Control certificate to SHA256 in 2017.1 and older agents are unable to decrypt the certificate. Click here for more detail.
We see this issue more often with customers who upgrade from 9.6 to 2017.3, but this can affect anyone upgrading from previous versions of LANDesk to Ivanti 2017.x
Upgrade your agents by clicking Rebuild all under Tools>Configuration>Agent Configuration. Once that completes, right click your agent configuration and choose schedule agent deployment.
You may be able to get the older clients to function again if you replace the following file with the one from %LDMS_HOME%ldlogon on the core server.
C:\Program Files (x86)\LANDesk\LDClient\issuser.exe