On attempting to install updates the client was failing with the error code 66A, this is due to corrupted install files when attempting to update the Microsoft .NET Framework 4 Client Profile. In order to resolve this and install updates successfully perform the following:
1) Browse to Start > Control Panel > Programs > Uninstall a program.
2) Select ‘Microsoft .Net Client 4 Profile’ and Uninstall.
3) Choose to ‘Repair .NET Framework 4 Client Profile’ to its original state.
4) Once the repair is complete perform a restart.