Error while upgrading from VMware vCenter 5.1 to vCenter 6.0


I have not seen any special feature improvements in 5.5 over 5.1 that would have benefited our environment, and as with any other major new releases  was patiently waiting for VMware to come out with Update 1 for vSphere 6. Originally I had the SSO, VMware Update Manager, and vCenter each running on its own server. Databases for SSO and vCenter are separated to a standalone SQL 2008 R2 server.   I ended up combining the VUM and vCenter on one single server, and upgrading the SSO to PSC (Platform Services Controller) and kept it separate, in case if we go with 2nd vCenter in the future.

Upgrading vCenter from 5.1.x to 6.0 is quite straight forward process, mount the vCenter 6 VMware-VIMSetup iso image to the vCenter server, and run the installer. It will recognize that there is a previous version installed and offer you to upgrade it.But first, make a backup of working production servers, before the upgrade. Shutdown the VMs, and copy the SSO and vCenter vmdks to a separate folder – in case if snapshots decide to take a break from work. Take the SSO, vCenter snapshots, and of course backup the SQL databases, if you have them running separately.

Don’t despair, if you receive the below error during vCenter upgrade:

problem authenticating into the legacy vCenter Server using the credentials
problem authenticating into the legacy vCenter Server using the credentials


First try the troubleshooting steps outlines by Sander at

Then check the Upgrade logs under C:\Users\%YourUsername%\AppData\Local\Temp\vcsUpgrade\UpgradeRunner.log to find out what is exactly is failing, if the VMPros troubleshooting did not help.

It did not recognize the password, as in my case, and could not connect to the Inventory Service.


The solution was to change the “Administrator” to “admin@system-domain”, if you upgrading from vCenter 5.1.

Try using “administrator@vsphere.local” account, if you are upgrading from vCenter 5.5.

Going forward it will ask you for an “Administrator” password couple of more times, this time for the newly installed PSC a.k.a SSO server, so don’t confuse them.


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