If the Exchange GRE fails to load after push upgrade to A.09.06 or later you will need to re-register the assembly manually. After doing this the MMC will load properly and GRE works ok.
1. Open command prompt and enter command: if OS used is Windows 2008, enter: cd "C:\Windows\Microsoft.NET\Framework64\v2.0.50727" if OS used is Windows 2012, enter: cd "C:\Windows\Microsoft.NET\Framework64\v4.0.30319"
2. Run following command in command prompt: InstallUtil.exe "C:\Program Files\Hewlett-Packard\Exchange Granular Recovery Extension\bin\ExchangeGre.MmcGui.dll" /i
Regards,
Sebastian Koehler