Directly connecting two Windows 10 Pro PCs via a crossover cable creates an isolated network segment that often defaults to the "Public" profile, which disables password-protected sharing. To enforce authentication on bi-directional shares, you must manually assign each adapter to a "Private" network profile and explicitly enable password protection in Advanced Sharing Settings. This ensures that unauthorized users cannot access shared resources without valid credentials.
Understanding the Network Profile Barrier
The primary reason password protection fails in this specific setup is how Windows categorizes network connections. When you connect two computers directly with a crossover cable (or a modern auto-MDI/MDIX Ethernet port), Windows typically detects the connection as an untrusted network. By default, it applies the "Public" network profile. The Public profile is designed for maximum security in coffee shops or airports, meaning it hides your PC from other devices and turns off file sharing features entirely, including the ability to prompt for passwords. To fix this, you need to treat the direct link as a trusted home or office environment. You can change the network profile by navigating to Settings > Network & Internet > Ethernet. Click on the connected Ethernet adapter and switch the profile setting from "Public" to "Private". This action tells Windows that the network is under your control, allowing you to configure sharing permissions securely. Without this step, any changes to sharing settings may be ignored or reset because the system assumes the network is unsafe for local resource discovery.Enabling Password-Protected Sharing
Once the network profile is set to Private, you must ensure that the specific sharing protocol requires authentication. Open the Control Panel and navigate to Network and Sharing Center. From there, click on Change advanced sharing settings in the left sidebar. You will see three main sections: Private, Guest or Public, and All Networks. In the Private section, locate the option labeled Password protected sharing. Ensure this is turned On. If it is turned off, anyone on the same network segment can access shared folders using anonymous guest accounts. Turning it on forces Windows to require a username and password that matches an account existing on the host machine. It is critical to perform this configuration on both computers if you want bi-directional sharing where both machines can protect their own outgoing shares while accessing the other. For more details on general LAN file sharing configurations, see Enable WIN10/11 LAN File Sharing.Configuring User Accounts for Access
Enabling password protection only works if the remote user has a valid account on the host system. Since these are two distinct physical machines, they do not share a domain controller or automatic credential sync. You must create identical user accounts on both PCs if you want seamless access, or use the credentials of one PC to log into the other. Navigate to Settings > Accounts > Family & other users and add a new local user account. Give this account a strong password. Then, go to Settings > Accounts > Your info and change the account type to Administrator if needed, though standard user rights are often sufficient for file access. On the second PC, repeat this process. When you try to access a shared folder on PC A from PC B, Windows will prompt you for credentials. Enter the username and password created on PC A. If you prefer not to create duplicate accounts, you can use the built-inAdministrator account, but note that Microsoft recommends against using the default Administrator account for daily operations due to security implications. Alternatively, you can map network drives using the net use command in Command Prompt to store credentials permanently, avoiding repeated prompts.
Verifying Share Permissions and Security Settings
After configuring the network and user accounts, you must verify the actual folder permissions. Right-click the folder you wish to share and select Properties, then go to the Sharing tab. Click Advanced Sharing and check Share this folder. Here, you can manage who has access. Click Permissions to define whether users have Read, Change, or Full Control rights. Next, switch to the Security tab. This is a common point of confusion. The Sharing tab controls network access, while the Security tab controls local NTFS permissions. Both must allow the user account you created. If the Security tab does not list your user, click Edit > Add and type the username. Ensure that the user has at least Read & Execute permissions. If you encounter issues where the share appears but access is denied despite correct passwords, check the Local Security Policy. PressWin + R, type secpol.msc, and navigate to Local Policies > Security Options. Look for Network access: Sharing and security model for local accounts. Ensure this is set to Classic - local users authenticate as themselves. If it is set to Guest-only, password protection will be bypassed.
For further insights on managing access restrictions, review Allowing LAN Access on Windows XP and Windows 7 Machines: A Security Consideration.
Troubleshooting Common Connectivity Issues
Even with correct settings, connectivity problems can arise. First, ensure that both PCs are on the same subnet. In a direct crossover connection, Windows usually assigns IP addresses automatically via APIPA (Automatic Private IP Addressing) in the range 169.254.x.x. If one PC has a static IP or a different subnet mask, they cannot communicate. You can check this by opening Command Prompt and runningipconfig.
Second, verify that the Function Discovery Resource Publication service is running. This service allows your PC to be discovered by other devices on the network. Go to Services.msc, find the service, and set its startup type to Automatic. Restart the service after changing the network profile to Private.
Finally, test the connection by pinging the other PC's IP address from the Command Prompt. If the ping fails, check your firewall settings. Windows Firewall should allow File and Printer Sharing rules for the Private network profile. If the ping succeeds but file sharing still fails, restart the Lanman Workstation service on both machines to refresh the network stack.
Frequently Asked Questions
Why can't I see the other computer in Network Explorer?
Windows 10 disables network discovery by default on Public networks. Switching the Ethernet adapter to a Private profile enables discovery. Additionally, ensure the Function Discovery services are running on both machines to allow them to broadcast their presence to the network.
Do I need to disable the Windows Firewall for direct connections?
No, disabling the firewall is insecure and unnecessary. Instead, ensure that the "File and Printer Sharing" exceptions are enabled specifically for the Private network profile in Windows Defender Firewall settings. This allows traffic on ports 445 and 139 while keeping other threats blocked.
Can I use a standard USB Ethernet adapter instead of a crossover cable?
Yes, most modern Ethernet adapters support Auto-MDIX, which automatically adjusts the pinout to handle straight-through cables. However, verifying that both PCs receive an IP address via ipconfig is essential to confirm the physical link is active regardless of cable type.
What if I forget the password for the shared folder account?
If you forget the password for the local account used for sharing, you must reset it on the host machine itself. Navigate to Settings > Accounts > Sign-in options and change the password. Once changed, you must use the new password when accessing the share from the client machine.
Is it safe to share folders over a direct crossover cable?
Yes, it is generally safe provided you use strong passwords and keep the network profile as Private. Since there is no internet gateway involved, the risk of external attacks is minimal. However, always ensure that sensitive data is encrypted or restricted to specific user accounts to prevent unauthorized local access.