I used FrontFace Lockdown (FFL) to configure a kiosk user on a Mac that had both MacOS Sierra and Windows 10 installed. This was all on the Windows 10 partition. There is one admin account and a second user "mac", which is automatically logged in (without password). Then Chrome is started in kiosk mode (-kiosk flag). With FFL I configured the user "mac" so that all hotkeys such as Ctrl+Alt+Del, Win+L etc. were disabled, and logging out or changing users was disabled too. The user could only use Chrome or turn off the computer.
The one way to log into the admin account (to stop the auto-login basically) was to hold down Shift at boot, which worked just fine before I applied the FFL configuration. I was able to stop the automatic login and choose which user to log in as.
Now, however, this doesn't seem to work. I feel like it might be because the keyboard isn't recognized before logging in. I tried pressing caps lock and observing when the caps lock light turned on, and it usually turns on just before logging into "mac". I tried different keyboards (USB and Bluetooth) as well.
There's an option in FFL to disable "shift at boot to stop automatic login", but I'm very sure I didn't select it.
How can I login to this computer as an admin user?
There is also an alternate possible way. I let FFL create a system restore point before applying the configuration. If there is a way to restore the system to this point that would also solve my problem.
At worst, restoring/resetting Windows 10 to factory setting would be fine too, as there is no data on the PC and setting up the users etc. wouldn't take too long.