One of the most annoying things that I have seen with Windows 10 since the October 2018 Creator's Update has been that shared folders have not been working consistently, sometimes AT ALL. When you are trying to run a small business, and you all of a sudden can't access your files because your computer installed updates without your permission (another annoyance, we'll shelve that one for now though), you certainly end up looking like a fool to your customer waiting patiently for you to get a copy of the invoice they requested. Anyways... after a few months of just working around it, I have finally taken the time to sit down and figure out WHY the folders I had shared on my Windows 10 machine were no longer accessible, and fix the problem.
A handful of little issues have been responsible for many people' file shares and mapped network drives to stop being accessible. After the WannaCry outbreak in early/mid 2017, which used a decades-old bug in the SMBv1 protocol, Microsoft quickly released a patch to disable SMBv1 for all users. Since SMB is an integral part of legacy Windows File Sharing, it obviously broke a lot of people's shared folders, making them inaccessible. Dozens of patches and large updates later, Microsoft has worked around the problem (more or less), and file sharing can be used fairly reliably again, if you know how to turn it all back on and reconfigure it.
We'll break this down into simple steps with pictures. Simple steps are good, and pictures are worth a thousand words. I'm not sure I know 1,000 words anyways. But before we do that, here's a summary of the steps:
Simple enough, right? Yeah, summaries always are. Alright, let's do this.
Start out by opening Windows Explorer, and navigating to the folder or drive that you want to share. Right click on it, and select "Properties" . In the new window that opens, click on the "Sharing" tab, and then click on the "Advanced Sharing" button. From this new window, click on the "Share this folder" checkbox to check it. By default, this will give you Read-Only access to this specific folder when you connect to it from another computer. If you need write access/full control, click on the Permissions button and modify the shared folder's permissions as necessary. When done, click on the "Ok" button to close the Advanced Sharing window, and then click the Apply button on the Properties window (if it isn't locked), and then the "OK" button to close the properties window. Step 1 complete, not too painful.
The next step in this process is to make sure that the computer hosting the shared folder can see other computers on the private network, can be seen by other computers on the private network, and has File and Printer Sharing enabled. Open the Windows Start menu, and type "control panel'. Open the Control Panel application and navigate to "Network and Sharing Center" , and then "Advanced Sharing Settings" . From here, you should see three different groups labeled "Private" , "Guest or Public" , and "All Networks" .
Under the "Private" group, make sure the "Turn on network discovery" and "Turn on file and printer sharing" options are selected.
Under the "Guest or Public" group, make sure both options are turned OFF (unless you have a legitimate need to have them on, you will know if you do).
Finally, under the "All Networks" group, you will want to change two settings. The first one, under "File Sharing connections" dictates the strength of encryption used to keep your files safe in transit. Obviously, stronger is better, but a lot of older devices DO NOT support the stronger encryption. If you have any computers on your private network that are not Windows 10, but need access to the file shares, change this option to "Enable file sharing for devices that use 40- or 56- bit encryption" . Last but not least, if you want to be able to access file shares on this computer without a username and password on the computer itself then select the "Turn off password protected sharing" option. This will allow you to connect to file shares on this computer without having to have a user account/password on the machine.
This step is relatively easy, and doesn't require a lot of explanation. From the Windows Control Panel, open the Network and Sharing center, and click on the "Change adapter settings" option on the left side of the window. This will open a window that will show all of the physical network adapters you have on your computer. You will want to do the following for every network adapter you see in the window (NOTE: generally, there are only one or two in this window): Right click on the network adapter, and select "Properties" from the popup menu. In the Properties window, verify that the "Client for Microsoft Networks" and "File and Printer Sharing for Microsoft Networks" options are both checked. Click OK to close the window. That's it. Still with me?
This next step may ask you to reboot your computer. If so, say "reboot later" ; we'll do it after the last step. Open the windows Start menu and type "windows features" . You should see a "Turn Windows features on or off" option in the list, click it. When the window loads, it will give you a variety of additional features that can be enabled or disabled for Windows. Scroll down to the " S' section. From here, make sure that the "SMB 1.0/CIFS File Sharing Support" option is NOT checked, and the "SMB Direct" option IS checked. SMBv1 is unsafe, so we definitely don't want to use it. On the other hand, SMB Direct uses SMB v3, which is inherently more secure, and can make your file sharing much faster if your network adapter(s) support it. If your network adapters do not support it, no loss. It won't hurt anything to have it enabled. Click on the "OK" button at the bottom of the window to apply the feature changes.
The last thing that we will want to check before we reboot the computer is the built-in Windows Firewall. To open the firewall, open up the Windows Start menu, and type "firewall" . There should be an option for "... Firewall with Advanced Security" . Open that one. In the new window that opens, you should see the firewall status, it should be turned ON (please, please don't turn it off!). On the left side of the window, you should see buttons for "Inbound Rules" and "Outbound rules" . Click on each of these buttons, and scroll down the list in the middle of the window to the 'F' section. You want to look for all of the "File and Printer Sharing entries" . There are multiple entries that have the same name, but are applied to the different firewall profiles (Private, Domain, and Public). At bare minimum, you want to make sure that all of these entries are ENABLED for the Private profile, and the rules are set to ALLOW. Be sure to check the Inbound and Outbound rules, if one or the other are not configure correctly, the firewall could block file share access. Once you have verified that the firewall is configured correctly, close the window.
Before you do anything else, reboot your computer. Once you have done that, you can try to connect a second computer to the newly configured file share. At this point, you should have no trouble connecting to your new file share!