Fix OneDrive Error 0x8004de40 - Sign-in & Sync Repair

You are staring at a crossed-out cloud icon in your taskbar, and OneDrive refuses to sign in no matter how many times you click. Your computer has lost its secure handshake with Microsoft's servers, usually because your network settings are cached incorrectly or your system clock has drifted by just a few minutes.

Why this happens

Your computer is failing to establish a secure connection with Microsoft servers. This is almost always caused by stale network configuration or a system clock that does not match the server's time.

Steps

1. 01
   Press the Windows key, type 'cmd', right-click it, and select 'Run as administrator'
2. 02
   Type 'netsh winsock reset' and press Enter
3. 03
   Type 'netsh int ip reset' and press Enter
4. 04
   Type 'ipconfig /flushdns' and press Enter
5. 05
   Right-click your system clock in the bottom right corner and select 'Adjust date and time'
6. 06
   Click the 'Sync now' button under 'Synchronize your clock'
7. 07
   Restart your computer
8. 08
   If the error persists, open OneDrive Settings, navigate to the 'Account' tab, select 'Unlink this PC', and sign back in