It's critical to check your environment end to end for compatibility issues prior to upgrading VMware Horizon View. Unfortunately, VMware has made Horizon View product incompatibilities easy to stumble across if the prerequisite documents are not studied before an upgrade. The version numbers do not imply compatibility with Horizon View. For instance, Horizon View 5.1 was not compatible with the first release of vCenter 5.1 when it came out.
Tip
For more details about VMware product interoperability visit the matrix webpage at http://partnerweb.vmware.com/comp_guide2/sim/interop_matrix.php.
When upgrading VMware Horizon View, a vCenter upgrade is commonly accompanied.
Note that there is a specific order and compatibility requirements when upgrading vCenter and its various accessory products.
In particular, the following order should be followed when upgrading Horizon View and vCenter:
vCenter SSO (if external)
View Composer
View Connection Servers
vCenter Server
ESXi...