Many users elect to install or continue to use "older" versions of VMware vSphere. The primary reason for this is that up to and including vSphere 6, you can continue to use the traditional Windows (C#) client for most administrative tasks. Beginning with vSphere 6.5 the dreaded Web Client becomes the ONLY choice, leaving many day-to-day users with a case of "upgrade apathy" for the latest versions of VMware vSphere.
Recently, Andrew Schaeffer encountered a vSphere 5.5 environment in need of attention. Basically, General Support for vSphere 5.5 ends on September 19, 2018. These folks needed to upgrade right away. They elected to upgrade to vSphere 6.0, which will give them General Support until 2020.
When Andrew attempted to install/upgrade to the latest build of vCenter Server Appliance (VCSA) 6.0 using the Clients Windows 10 and Server 2012 systems, he found that the Client Integration Plugin (CIP) failed to install. He tried every VMware KB and VMware Community Support Forums post that he could find. Then even opened a case with VMware Support! The issue was that the most recent browser updates are simply not compatible with the notorious security flaws of the Client Integration Plugin.
In the end, Andrew built a Windows 7 VM and made an OVA (Virtual Appliance) that he could import into vCenter 5.5. The theory was that an older OS, with older (non-updated) browsers might install the CIP, and it worked!
How ironic is it that Andrew had to use a no-longer-supported OS to upgrade a barely-still-under-support version of VCSA to a still-supported-for-two-years version of VCSA!
Legacy vSphere Systems Support
VMsources has been working on VMware systems since the days on ESX 3 and Virtual Center 2.0! We are pleased to provide support and upgrades to all versions of vSphere and even older Infrastructure 3 systems. We have the knowledge and experience you need to get your problems resolved, no matter what the vSphere version!