One of my clients faced the following error, while starting an 12.2 database service on Windows:
OHUC-1026 : unable to authenticate the new password
Background:
The client was trying to change the Oracle Home User password using the orahomeuserctl, after that he was not able to start the Database Windows Service.
What is Oracle Home User?
Oracle Home User is used to run the instance services (You still install the software as Administrator).
In Oracle Database 12.1, there are 3 choices for this user:
Use existing Windows user, Create new Windows user or SYSTEM (Use Windows Built-in account)

In Oracle Database 12.2 and above, we have additional option of using Virtual User:

Please note that you cannot change the Oracle Home User once the installation is complete. To change the Oracle Home User, you must reinstall the Oracle Database software.
The steps to change the password of this user are as follows:
1- Change this user password at the Windows Level.
2- Use the orahomeuserctl to change it password at the Oracle Level (This will update the passwords of the Database Windows Services).
The steps of using the orahomeuserctl utility to change the password are as Follows:
– Open a Command Window
– Set the oracle environment to that of your database
– Use the following command to change the password:
orahomeuserctl list | updpwd [-user username] [-host hostname1, hostname2, . . .] [-log logfilename]
This tool updates the password for Windows services in the Oracle home. The input password must match the password for the Windows User Account used as the Oracle Home User. So, first use the Windows operating system tools to change the Windows password and then use this tool to update the Windows services in the Oracle home to use the same password.
If after doing the above steps, your are still getting the above error [OHUC-1026], then ensure that the user is not locked at the Windows level (This was the case of my client)
For more information about changing the Oracle Home User Password, please refer to: