Windows 10 V1809: Upgrade deactivates Build-In Administrator

[German]A brief note for Windows 10 users working with the Build-In Account Administrator. When you upgrade to the October 2018 update (Windows 10 v1809), this account is disabled in some cases.

Background information

In Windows 10, there is a built-in user account called Administrator, which is disabled by default. I remember, this account was already present in Windows XP – but I can't test it at the moment. 

• The account is deactivated by default during setup (imho during the OOBE phase) if a second administrator account is created during setup. 
• Since Windows Vista, this administrator account does not need a user account control query to assign administrative permissions to tasks.

Microsoft provides this Build-In-Administrator for emergency cases: If no second administrator account exists in Windows, the account will be activated. On the other hand, this means that the account is deactivated during setup when the OOBE phase is performed.

Don't use the Build-In Administrator

I recommend to let that Build-In account Administrator disabled. Because if this user profile becomes corrupted and no other user account with administrator rights exists anymore, usually only a new installation of the operating system remains.

If, on the other hand, the second administrator account or its password is getting lost and the Build-In Administrator account is deactivated, the system can usually be rescued with a hack. At the end of the article I linked blog posts that show how to activate this administrator account in a Windows PE environment. I have successfully used this several times to save systems.

Attention when upgrading from V1803 to V1803

The Technet team from Microsoft Japan has published a blog post entitled Upgrading from Windows 10 version 1803 to version 1809 will invalidate built-in Administrator, which deals with the issue of Build-In Account Administrator when upgrading from Windows 10 V1803 to version 1809. The statements:

• If you upgrade to version 1809 with Windows 10 version 1803 and Build-In Account Administrator enabled, the account can be disabled.
• The account is not disabled when the feature update is installed if there is no other administrator account. 

  If a second administrator account exists and is enabled, Setup disables the Build-In Administrator account when you upgrade to Windows 10 V1809 during the OOBE phase.

Personally, I would have said that's the behavior I expected. However, the Technet team from Microsoft Japan writes that the developers at Microsoft are currently working on solving this issue. Microsoft is currently working on releasing a patch by the end of January 2019. 

Some workrarounds

If you need to upgrade before the patch is released, make sure that you can log in with a different administrative user account than the built-in administrator.

Has an upgrade been performed and is the built-in administrator then disabled? Then log on to the remaining administrator account and activate the Build-In Administrator. This can be done in an administrative prompt using the command:

net user administrator /active:yes

In Windows 10 Pro / Enterprise you can use the extended user administration. To do this, open the computer administration with administrative authorizations and double-click on the Administrator account.

Then enable the disabled administrator account in the properties via the Account is enabled checkbox (which I don't really recommend for the above reasons).

However, if the second administrator account is damaged, the above approach does not work anymore. Then you can try the approaches I described in the article series Activate Build-in Administrator account in Windows – I. (via)

Similar articles:
Activate Build-in Administrator account in Windows – I
Activate Build-in Administrator account in Windows – II
Windows: Yes button in user account controls is disabled
Windows 10: file system error (-1073741819) – 'extended attributes are in consistent'
Windows 10: Open command prompt window as administrator