Lost Connection: Troubleshooting OneDrive Network Error 0x8004de40

Seeing error code 0x8004de40 means OneDrive is completely cut off from the cloud. This is strictly a network communication problem. It usually happens when your internet connection is unstable, a security program is blocking the app, or your Windows security protocols are misconfigured.

Here is how to restore your connection and get your files syncing again.

Fix 1: Check your VPN and proxy settings

Virtual Private Networks and strict proxy servers often block the background traffic OneDrive uses to communicate with Microsoft servers.

1. Turn off any active VPN software on your computer.
2. Click the Start button and open Settings.
3. Go to Network & internet and select Proxy.
4. Make sure Automatically detect settings is toggled on.
5. Turn off any manual proxy setups.
6. Open OneDrive and see if it connects.

Fix 2: Enable TLS protocols

OneDrive requires specific security protocols to securely talk to the cloud. If TLS 1.2 is disabled in your hidden Windows internet settings, the connection will instantly fail and trigger this exact error.

1. Press the Windows key + R to open the Run box.
2. Type inetcpl.cpl and press Enter.
3. Click the Advanced tab at the top of the new window.
4. Scroll all the way down to the security section.
5. Make sure the boxes next to Use TLS 1.2 and Use TLS 1.3 are checked.
6. Click Apply and then OK.
7. Restart your computer and try opening OneDrive.

Fix 3: Reset your network sockets

If your internet works perfectly in your web browser but OneDrive is still blocked, your core Windows network stack might be corrupted. Resetting your network sockets clears out bad routing data.

1. Click the Start button and type cmd.
2. Right click on Command Prompt and choose Run as administrator.
3. Type the following exact command: netsh winsock reset
4. Press Enter.
5. Restart your computer to apply the fresh network settings.
6. Launch OneDrive.

Fix 4: Switch your DNS servers

Sometimes the default Domain Name System provided by your internet company struggles to resolve Microsoft server addresses. Switching to a reliable public DNS can clear the blockage.

1. Press the Windows key + R to open the Run box.
2. Type ncpa.cpl and press Enter.
3. Right click your active Wi-Fi or Ethernet connection and select Properties.
4. Double click on Internet Protocol Version 4 (TCP/IPv4).
5. Select Use the following DNS server addresses.
6. Enter 8.8.8.8 for the preferred server and 8.8.4.4 for the alternate server.
7. Click OK on both windows and test your OneDrive connection.