There's one last issue regarding permissions:
If you have "nested" folders, all folders in the path the shared folder must have the same permissions.
For example:
/music
If Everyone has Read and Write - it's wide open.
/serverfolders/music
In this example, there are two different folders. If serverfolders has a more restrictive permission, it will stop access to the sub-dir music.
(If you followed the on-line build example, closely, this shouldn't apply.)
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Your observations from your searches are right. A lot of people are doing this, to include yourself, at first. "That", the change, is why I turned a skeptical eye toward Win10. M$ is infamous for pushing out security changes and leaving the masses to deal with unintended consequences.
There are other possibilities such as the firewall software you're using. (You could try turning it off - just don't surf the Net with your firewall off.)
Also, your router may be interfering. If you turn your router off for a test, you'll lose DNS (name service). You can still access your R-PI on the local LAN direct using the Raspberry PI's IP address, typed in the windows file explorer address bar.
((Substitute the IP address for your R-PI in, using the following format. -> \\192.168.1.35\sharename Or you could try just the IP address \\192.168.1.35, and see if your share shows up.))
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What it boils down to is, if you had it working at some point, odds are that something changed along the way. This tends to be things like automated software updates (Windows, the firewall, the router and even OMV, if you updated it AFTER you had access to your share.)
If you plan on sticking with this, you're going to need a way to look at the file structure on your R-PI and, eventually, for editing config files without using the command line. I'd recommend installing WinSCP on one of your Windows machines. From Windows, WinSCP will allow you to access OMV as root, in a Windows explorer style graphical environment. I think you'll find it useful for exploring OMV (and for looking directly at permissions assigned to files and folders).
On the first use of WinSCP - on the login page:
Hostname: The IP address of your R-PI
User name: root
Password: openmediavault
(The password above is the default, and assumes that you didn't change anything during your R-PI setup. Note that the WebGUI only changes the password for the Web admin account.)