I have an error of 8506,421 that my Norton software can not fix
Here is the KB article on Error 8506,421. - https://support.norton.com/sp/en/us/norton-core/current/solutions/v80281719_EndUserProfile_en_us?filter=&q=8506%2C421
Let us know how you get on.
Is your Norton Product working? Can you access the functions such as scans etc?
There are currently 8 users online.