Hi,
make sure of below prerequisites.
vCenter Hardware Pre_Requisites,
Processor:
1. must be 64-bit Processor ( intel/AMD).
2.what are number of logical cores:_____
3.what is the each core speed:____
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vCenter Hardware Pre_Requisites
Memory:
12GB.
Hope u are running vcenter server and its database on the same server
so
1GB( Vmware vcenter mgmt webservices )+ 2GB(inverntory services )+3GB profile-driven storage service.
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note: synnchronize clocks of all machines in vsphere network.
1.vcenter server should be not be installed on a DC
2. vcenter server should be joined as member of the DC member.
3. user account used to install vCenter server should have following permissions
1. Member of administrator group
2.Acts as a part of the operating system
3. log on as a service
VC server 5.5 supports connections bet vc and its componets only by IPv$ addressing,
if ur are using ipv6 then u should use fqdn or hostname of the vcenter.