I am experiancing exactly the same in our new ePO 4.5 environment
I have also used registred LDAP server (to DNS domain name or direct server or to IP4) and configure server in the AD sync setting
Loading of the Active Directory container list takes up to 30 minutes!
I have around 400 mapping points!
I really need this solved.
Did you solved it at this moment??
Unfortunately not. They eventually told me patch 2 would fix it but low and behold I have another ticket open because patch 2 fails to install. I've pretty much given up calling support is the same old scenario collect logs and wait. Testing trendmicro...