After drive encryption computer boot shows only black screen with cursor, no login. Symantec Endpoint Encryption 11.1.2 HF2 was installed, and encryption reported successful completion. This happened on a Lenovo T470 only.
A single setting for Windows wifi connection caused the issue: Under wifi network configuration in Computer Configuration > Policies > Windows Settings > Security Settings > Wireless Networks under Advanced settings on the Security tab there is a section for Single Sign On. If the single sign on to "Perform immediately before User Logon" is enable, the machine will present a black screen with a mouse cursor instead of a logon prompt. Pressing CTRL-ALT-DEL at that point just flashes the blue background and then goes back to black, can't login.
SEE 11.1.2 HF2
Windows 7
Lenovo T470 only
Switching this setting to "Perform immediately after User Logon" brings up the login screen normally and login proceeds.