general

Files Not Syncing Across Devices

Resolution Checklist

  • 1 Understand Multi-Device Sync Failures
  • 2 Resolve Sync Breaks on Windows Devices
  • 3 Fix Sync Disconnections on macOS Devices
  • 4 Verify Account IDs and Port Configurations
  • 5 Summary Quick Reference Checklist

Files Not Syncing Across Devices

“Files Not Syncing Across Devices” occurs when files created or edited on one computer (Device A) do not appear on another computer or mobile phone (Device B), despite the cloud client showing “Up to date”. This breakdown prevents remote collaboration and compromises offline accessibility.

This guide provides troubleshooting steps, network port tests, and account audits to repair the sync pipeline on both Windows and macOS.

1. Understand Multi-Device Sync Failures

Cross-device sync failures are typically caused by:

  • Account Identity Mismatch: Being signed into a personal account on one device and a work/school tenant account on the other.
  • Stalled Client Application: The sync app process is hung on one of the devices, preventing local changes from reaching the cloud server or vice versa.
  • Network Port Blocks: Local firewall or router blocking essential HTTPS port 443 or websockets used for push notifications.
  • Out-of-Sync Local Clocks: A device with clock drift cannot correctly merge revisions, causing the server to ignore its updates.

2. Resolve Sync Breaks on Windows Devices

On Windows, you can test cloud endpoint connections and restart the sync host processes.

A. Test Outbound Connections to Cloud Ports

Verify that Windows can communicate with the cloud sync server endpoints (example tests for OneDrive and Google Drive):

  1. Search for PowerShell in the Start Menu and open it.
  2. Run the Test-NetConnection cmdlet: 
    # Test connectivity to Microsoft OneDrive endpoints
Test-NetConnection -ComputerName odwebservice.onedrive.com -Port 443

# Test connectivity to Google Workspace endpoints
Test-NetConnection -ComputerName drive.google.com -Port 443

If “TcpTestSucceeded” is False, check your local firewall or network router for outbound blocks.

B. Force-Restart the Windows Sync Engines

If connections are healthy but sync is stuck, kill and restart the local client (example for OneDrive):

:: Kill the desktop sync client
taskkill /f /im OneDrive.exe

:: Relaunch the client manually
start "" "%LocalAppData%\Microsoft\OneDrive\OneDrive.exe"

3. Fix Sync Disconnections on macOS Devices

On macOS, verify network sockets and force the file-provider background engines to restart.

A. Test Socket Connectivity via Terminal

Verify network connection routes to your cloud service using nc (netcat):

  1. Open Terminal (via Spotlight).
  2. Run the netcat command: 
    # Test connection to the cloud servers on Port 443
nc -zv-w 5 api.dropboxapi.com 443
nc -zv-w 5 api.onedrive.com 443

A successful connection returns “Connection to [host] port 443 [tcp/https] succeeded!”.

B. Terminate macOS FileProvider Domain Engine

Force macOS to restart the background file synchronizers:

# Terminate the FileProvider process
sudo killall -9 fileproviderd

C. Standardize macOS Time Settings

If clock sync is disabled, macOS cannot evaluate file modifications accurately:

# Force clock synchronization with Apple's NTP server
sudo sntp -sS time.apple.com

4. Verify Account IDs and Port Configurations

Verify configuration states in the cloud portal and client menus.

A. Audit Signed-In Credentials

  1. Open the cloud client application window on both Device A and Device B.
  2. Open Settings or Preferences and go to Account.
  3. Compare the exact email address and tenant name. For instance, derek@company.com (business account) is separate from derek@outlook.com (personal account), even if both utilize OneDrive.

B. Toggle Selective Sync Settings

Ensure the folder you are modifying is checked to sync to the target device:

  1. Open cloud client Preferences > Sync (or Choose Folders).
  2. Verify that the checkbox next to the folder containing the missing files is checked. If unchecked, the files exist on the cloud but will not sync to this specific device.

5. Summary Quick Reference Checklist

Action TargetOperating SystemTerminal Command / PathExpected Outcome
Verify Port 443Windows (PowerShell)Test-NetConnection -ComputerName <host> -Port 443Verifies outbound firewall ports are open.
Verify Port 443macOSnc -zv <host> 443Confirms the Mac can reach cloud API servers.
Restart OneDriveWindowstaskkill /f /im OneDrive.exeClears frozen local sync worker threads.
Restart FileProvidermacOSsudo killall -9 fileproviderdRestores frozen system-level file-system bridges.
Resync NTP ClocksmacOSsudo sntp -sS time.apple.comStandardizes file timestamps to avoid sync drops.
Verify Selective SyncClient SettingsPreferences > Choose FoldersEnsures folders are not hidden on specific devices.