Hi Guys, I am trying to install windows 10 version 1809 update and I keep on getting this error of 0xc1420121. I turned off KIS2019 and malwarebytes. What am I doing wrong, plz? Thx
Error 0xc1420121 is usually caused by if Windows isn't in good condition, i.e. it is damaged if you try to install an unsupported update when the temp folders are full (You have never cleaned them) if you use third-party antivirus programs that damage Windows's integrity PS! The heading is misleading, You have no problems with 1809 installing if it is already installed. So please correct the headline.
What tool? As long as we do not know, what is the reason, not possible recommend nothing. Maybe only remove those third party antivirus programs, clean all temp folder, check Windows and fix it if needed and then can try again. PS. what's the update which You tried to install and how You tried to install it? Did You used Windows update or something else?
I updated my laptop without issues after I uninstalled KIS2019 and MBAM so maybe that is the issue. Just had windows firewall and defender.
So it is not a clean install but an upgrade with KIS2019 active. I join Mr.X for this point. Do a clean install first.