Do not place the infrastructure master on a domain controller that is also a global catalog server
Preparing to demote one Domain Controller (DC), went to transfer the infrastructure operations master role to another DC first.
Had this question, however:
DC02 is a global catalog (GC) server. The infrastructure operations master role should be transferred to a GC server. Please see help for more information.
Are you certain you want to transfer the infrastructure operations master role to this GC server?
Are you certain you want to transfer the infrastructure operations master role to this GC server?
Checked the requirements for infrastructure master placement, and got the reason:
Do not place the infrastructure master on a domain controller that is also a global catalog server. If the infrastructure master and global catalog are on the same domain controller, the infrastructure master will not function. The infrastructure master will never find data that is out of date; therefore, it will never replicate any changes to the other domain controllers in the domain.
References
To remove the global catalog using Active Directory Sites and Services
https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/ad-forest-recovery-remove-gc
https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/ad-forest-recovery-remove-gc
Update