These symptoms typically occur when Lockdown Browser Is shut down improperly:
To restore the default settings on a Windows system, please use one of the methods described here:
https://respondus.knowledgeowl.com/home/how-to-restore-settings-on-a-computer
There's never a need to manually manipulate registry settings
To restore the default settings on a Mac System:
Start the system from a power down (not suspension)
Start Lockdown Browser
Immediately quit Lockdown Browser