Problem: Unhandled Exception occurred in your application and AD Sync tool crashes.
Reason 1: One of the reasons could be an older version of .Net Framework is running on the server where AD Connect Sync is installed due to which this exception error occurs.
Microsoft .Net Framework 4.8 must be installed on the machine prior to starting the installation. To fix this problem, make sure that you have installed the required .NET version and reboot the server after installing it. Pre-requisites can be confirmed from this documentation URL: https://help.hostingcontroller.com/OnlineHelp/default.aspx?pageid=pre_requisites
. Now re-run the tool by choosing the option “Run as Administrator
Reason 2: If this exception error occurred on the Cloud AD Settings tab, then it will be due to incorrect values or missing string keys in the registry for the AD Sync tool.
Solution: To confirm the required registry key, open the registry through the registry editor and go to this path HKEY_LOCAL_MACHINE\SOFTWARE\HCdirSync\Default\OU=path and confirm that the CloudADRoot key exists with a valid key. If it does not exist or is misplaced, then create a new string value registry key on the same path with the name CloudADRoot and then check the AD Sync tool.