When attempting to launch Control for the first time post server install or update an error message is shown stating that an Installation is currently in progress
Note: You will get basically the same message when you attempt to start the SSLIP
Sometimes it will be a totally different registry key that is affecting the situation. It doesn't always have to be Control that is causing the problem.
HKEY_Local_Machine\System\CurrentControlSet\Control\SessionManager\PendingFileRenameOperations
If there is a value set here that has data which is not readable as characters by the system, it will never remove itself on a reboot. This can cause a reboot cycle to happen during updates as it always thinks you need to get rid of this entry before moving forward.
You can either rename this to –PendingFileRenameOperations, or simply delete the key all together. It's usually better to rename it in case that information is needed later for referencing.