Another info, yesterday I went through Event Viewer but didn't find anything strange, except for a lot of DeliveryOptimization warnings with the following message:
"The policy DOGroupID was set with the value ", which is invalid and will be ignored."
Also ran a "sfc /scannow" which did point there were some corrupted files but wasn't able to fix them. Ran the "dism.exe /online /cleanup-image /restorehealth" but once it reached 100% it never completed the process, so I left it there processing until today.
But didn't work also, just logged onto one of the machines to find it with the same symptoms: On "This Pc" the disk appears but without space information, tried opening Disk Management but it is stuck at "Connecting to Virtual Disk service..."