As of chrome version 59, the option to drop the guest account is no longer present. This is a problem because if you enable supervised users that restrict access, the guest account will be available as a choice to any user, thereby circumventing any restrictions in place on supervised users.

There is a way around this issue. Type chrome://policy/ into your browser then uncheck the Show policies with no value set checkbox at the top right side of the window.

The one we want is called BrowserGuestModeEnabled . Next run regedit.exe and browse and set the following:

Registry Area HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry Path Software\Policies\Google\Chrome
Value Name BrowserGuestModeEnabled
Value Type REG_DWORD
Enabled Value 1
Disabled Value 0

Next, you will need to set this policy.

Cheers,
TK