When sysprepping Windows, before final shutdown:

  * open powershell/cmd and admin, cd to C:\windows\system32\sysprep

  * unplug the Ethernet cable/disconnect from Internet as Windows 10 will install apps on temp admin account which can cause sysprep to fail

  * do a sysprep -> audit -> reboot

  * then delete all local user accounts/profiles

  * in Win10, goto settings -> Update & Security -> Device encryption -> make sure bitlocker is turned off

  * then generalize and oobe