Windows 10 update error codes

You probably had a bad download or you don't have all the previous updates or don't have windows 10 already installed. Shutdown the computer and wait a couple of minutes and reboot and try again. First do a normal "check for updates"  to make sure you have all necessary updates.

You have not included any info needed to help -model computer, operating system, other errors, what windows update you're installing or if you are upgrading to win 10 and any other relevant info. You should have windows already installed and updated. Bitlocker needs to be turned off if you have it.

Windows 10 update fails with error code 0x80070002-0x20009 and message "The installation failed in the SAFE_OS phase with an error during PREPARE_ROLLBACK operation. Help!!

Mary may be right so I will just add, the error means what you show.  I cannot tell you exactly what happened from that error but it would seem to be involved with setting up a recovery operation in case the installed failed or you would require rolling the update back yourself. 

The link below shows how to determine the meaning, which you already have, but it also shows where some log files are which may hold info which would help pin down the problem.  It then goes on to describe some techniques to interpret the log files.. maybe it will help.

docs.microsoft.com/.../resolve-windows-10-upgrade-errors

The 8007002 part of the error means "File Not Found"