Fix ERROR_DEV_NOT_EXIST (0X00000037) Network Resource Gone

You're working, and suddenly Windows throws ERROR_DEV_NOT_EXIST (0X00000037) — "The specified network resource or device is no longer available." That's frustrating. Here's how to kill it and keep it gone.

The Fast Fix: Reconnect with Persistent Mapping

The most common cause? You mapped a drive or printer using a UNC path like \Server\Share, but Windows lost the connection. The real fix is to re-map it with the persistent flag so it reconnects every time you log in.

1. Open File Explorer (Windows key + E).
2. Right-click This PC and select Map network drive.
3. Pick a drive letter (say Z:).
4. In the Folder box, type the exact UNC path: \\ServerName\SharedFolder. Don't use an IP address unless you're sure it's static.
5. Check the box that says Reconnect at sign-in. This is the persistent flag.
6. Check the box Connect using different credentials if you need a specific username/password.
7. Click Finish. You should see the drive appear in This PC within a few seconds.

After clicking Finish, the drive should show up under This PC with the letter you chose. If you get a credentials prompt, enter them and check "Remember my credentials."

Why That Works

When you map a drive without the persistent flag, Windows treats it as a temporary connection. Reboot, network glitch, or even a sleep cycle — and it's gone. The 0X00000037 error means Windows tried to access that resource but found nothing at the path. The persistent flag forces Windows to re-establish the connection at every logon, using cached credentials if you saved them.

One thing I've seen trip people up: if the server name changes (someone renames the server or DHCP hands out a different IP), the persistent mapping fails. That's why I recommend using a UNC path based on the server's hostname, not its IP address. The hostname is usually stable.

Less Common Variations

Network Printer Gone

Same error, but for a printer. You try to print, and Windows says the device isn't available. The fix is similar — re-add the printer with a persistent connection.

1. Go to Settings > Bluetooth & devices > Printers & scanners.
2. Click Add device. If the printer doesn't show up automatically, click Add manually.
3. Select Add a printer using an IP address or hostname.
4. Choose TCP/IP device in the dropdown, type the printer's IP or hostname, and follow the prompts.
5. After it's added, right-click the printer and select Printer properties. Go to the Ports tab and make sure the port is set to Standard TCP/IP Port. If it's a WSD port (Web Services for Devices), delete it and add a TCP/IP port instead — those WSD ports drop connections all the time.

Group Policy Override

In a corporate environment, Group Policy might be removing your mapped drives. Check with your IT team. You can verify by running gpresult /r in a command prompt to see which policies apply. If a policy explicitly removes drives, you can't override it without admin rights.

Firewall or Security Software

Some security suites (looking at you, Norton and McAfee) block SMB traffic. If you've recently installed such software, try temporarily disabling it to see if the error goes away. If it does, add an exception for file and printer sharing in that program.

Prevention: Keep It From Coming Back

Here's what I tell every tech I train: once you've got the persistent mapping working, lock it down.

• Use hostnames, not IPs. If the server's IP changes, your mapping breaks. Hostnames are more resilient, especially if DNS is set up right.
• Save credentials. When you map, check "Remember my credentials." This way, you don't get prompted every time — and the persistent reconnection can happen in the background.
• Check your network profile. Go to Settings > Network & internet > Ethernet (or Wi-Fi). Click your network and set it to Private. Public networks block file and printer sharing by default.
• Enable Credential Manager. Type credential manager in the Start menu and open it. Under Windows Credentials, you should see entries for your mapped drives. If they're missing, you'll get prompted every time. You can add them manually by clicking Add a Windows credential.
• Disable IPv6 on the network adapter if you see sporadic disconnects. Sometimes IPv6 gets confused — go to Network Connections, right-click your adapter, select Properties, uncheck Internet Protocol Version 6 (TCP/IPv6), and click OK.

That's it. Fix it once, and you won't see 0X00000037 again unless something fundamental changes on your network. If it does, run through these steps again — they work every time.