Some Windows 10 updates make Shared Folders feature of VMWare Workstation to stop working. The disks mapped from that folders become inaccessible without a reason.
The reason is actually that the updates break the registry entries.
To fix them you need to run regedit.exe and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order key. There you will see "ProviderOrder" value. The contents of this value looks similar to "LanmanWorkstation,RDPNP,webclient". This list is missing one important value, "vmhgfs". The correct value should be "LanmanWorkstation,vmhgfs,RDPNP,webclient".
It is possible, that the value will be different in your case, and the point is to add "vmhgfs" close to the beginning of the list. Probably, right after LanmanWorkstation is the correct order.