We've noticed something interesting on Windows 10 Clients running Parallels Client 15.5.16283 with Single Sign-On enabled. Some Windows 10 computer systems will display a "Sign-on Options" on the Windows 10 logon screen with two different password options (in addition to PIN and/or Picture password options if enabled). Either password field works as it should BUT we've noticed if you use the second password option directly after installing the Parallels Client (and rebooting), SSO will not work. Instead you are prompted to enter Credentials when launching the Parallels Client. See logon screenshot attached. To recreate the issue: Completely uninstall Parallels Client, remove all registry keys, and purge any %appdata%\2XClient directories. Reboot. Install the Parallels Client with SSO. Reboot. At the Windows 10 logon screen, select the "Sign-in Options" link, select the second password option, and login. Launch the Parallels Client. SSO will not work. You will be prompted to provide credentials. If you log out and back in using the second password option SSO will never work. Log out. At the Windows 10 logon screen, select the "Sign-in Options" link, select the first password option, and login. Launch the Parallels Client. SSO will work. We haven't been able to extensively test this. We've been having SSO issues with a handful of Windows 7, 8.1, and Windows 10 computer systems but the "Sign-In Options" is only available in Windows 10. It could be something in our environment but I wanted to see if anyone else runing Windows 10 with Parallels Client v15.5.16283 is seeing two password options on the Windows 10 logon screen.