Best answer by Cinn
I had the exact same issue this week as well. Windows 7 x64 with the latest version of the desktop controller (7.2).
It looks like some incompatibility with the latest version of .NET Framework.
The problem started after Windows Update installed the important update:
"Microsoft .NET Framework 4.7 for Windows 7 and Windows Server 2008 R2 for x64 (KB3186497)"
I just uninstalled Microsoft .NET Framework 4.7 manually (through Control Panel > Programs and Features), then reinstalled the previous version of .NET Framework (4.6.2) that I got from Microsoft's website (just google "Microsoft .NET Framework 4.6.2 (Offline Installer)").
My Sonos Desktop Controller Program now starts up again.
Obviously, this is not a long-term solution - after all Microsoft made it an 'important' for a reason - but until Sonos fix the desktop controller so it plays nicely with .NET 4.7 it looks like the best option to get the desktop controller running again is to revert to .NET 4.6.2.