When trying to remove an AD user from a group, you get:
Error: 1374 (0x55E)
The user cannot be removed from a group because the group is currently the user’s primary group.
This is because Active Directory users must always be in at least one group. This group is called their primary group. If you are getting ERROR_MEMBERS_PRIMARY_GROUP and the user is in more than one group, you just need to change which group is the users primary group before you remove the user group the group.
To fix error 1374 and change the users primary group:
Open Active Directory Users and Computers
Find the user whose primary group you want to change
Double click the user
Go to the Member of tab
Select a group that you are not trying to remove the user from and click Set Primary Group
You should now be able to remove the user from the group without getting the User cannot be removed from a group because the group is currently the user’s primary group error.