After the last Windows 10 update (1803), our five Windows 10 Pro computers which are in a WORKGROUP local network (no domain) keep loosing their connection to two shared network drives on one of the computers.  Usually by restarting their computer (sometimes multiple times) they can see the shared drives.  Also, the following steps almost always fix the problem but again it only lasts for a day or two or sometimes a few hours.

1. Close all running programs.
2. Click on Start Menu and then rt-click on This PC and choose Properties.  
3. Click on “Advanced System Settings” on the left side of the window.
4. Click on Computer Name tab.
5. Click on Network ID button.
6. Accept the default of “This computer is part of a business network”.
7. Click on the Next button.
8. Change the setting to “My computer uses a network without a domain”.
9. Accept the default workgroup name of “WORKGROUP”.
10. Click on Next button.
11. Click on Finish button.
12. Click on OK.
13. Restart the computer.