“WinX”? Do you mean Windows 10?
Recent Microsoft Updates to Windows 10 will disable the SMB1.0/CIFS option. First thing to check, when the My Cloud disappears from Windows File Explorer, is to ensure the SMB1.0/CIFS option is enabled.
How to Enable SMB 1.0/CIFS File Sharing Support on Windows 10
Some users are reporting that after the last Windows 10 update (Build 2004) they had to update the My Cloud Driver entry in the Device Manager. Opening the Device Manager, locate the WDMyCloud entry (may be under Western Digital NAS or some indicate under Software Devices), right click on the entry and select Update driver.
Example Device Manager (Windows 10 Build 1909), your screen may look different:
