Hello Edgar,
Just out of interest. What lenguage of Windows are you using?
Please install WindowsInstaller-KB893803
1. Create a new local group named "Users." To do this, click Start, click
Run, type net localgroup Users /add, and then click OK.
2. Add the non-English language local Users group to the new Users group
that you created in step 1. To do this, follow these steps:
a. Click Start, right-click My Computer, and then click Manage.
b. Expand Local Users and Groups.
c. Click Groups.
d. Right-click the Users group that you created in step 1, and then click
Add to Group.
e. Click Add, type the object name of the non-English language local Users
group, and then click OK two times.
3. Try to install Windows Defender Beta 2 again.
I hope this post is helpfull.
Let us know how it works ºut.
Еиçеl