I was working on customers environment and had a problem with the vSphere UI 9.1 (have not check other versions), where some information was missing.
Link on a vSAN Cluster -> configuration -> vSAN -> Disk Managemnt, This was blank with this error message:
Unable to extract data. Check vSphere Client logs for detail
There was also problem with the vSAN Cluster -> Monitor -> vSAN -> Capacity view was empty, under legacy the same error message was there.
under VM -> summary the widget with usage was not showing values
The customer machine I was working was running Windows with a Danish language and settings, and this was the problem, using a Windows Server running with US language and settings was working fine
The fix is just to go to the vSphere UI setting for the user and set the language to English or whatever language you prefer.
