An important note is the change in the Vault 2015 products.
Vault Server is supported in the Windows Client operating systems such as Windows 7, Windows 8, Windows 8.1 only in the edition Vault Basic.
This mean Vault Server 2015 Wokgroup and Professional editon is currently unsupported with on Windows 7, Windows 8 and Windows 8.1.
However the Vault client (all edtions) is still supported on Windows 7, Windows 8, Windows 8.1
Please check also the system requirements for the 2015 Vault Products.