OneDrive Admin Checklist: shared library sync stays pending for slow networks

When a shared library sync stays pending for more than a few minutes on a slow network, users cannot access the files they need. This problem occurs because the OneDrive sync engine enforces a download bandwidth limit and a file scan timeout that are too strict for the available connection speed. This article explains the root cause and provides a step-by-step admin checklist to resolve pending sync on shared libraries over slow networks.

Why Shared Library Sync Stays Pending on Slow Networks

OneDrive uses a sync engine that scans all files in a shared library before it begins downloading. This scan process has a timeout that defaults to 30 seconds. On a slow network with high latency or low throughput, the scan cannot complete within that window. The sync engine then marks the library as “pending” instead of starting the download.

In addition, OneDrive applies a default download bandwidth limit of 1 Mbps when it detects a slow or unstable connection. This limit is intended to prevent the sync from consuming all available bandwidth, but it can actually keep the sync stuck in a pending state because the engine waits for the throttled throughput to complete the initial handshake with the server.

The combination of a short file scan timeout and an aggressive bandwidth throttle causes the pending status. The fix requires adjusting both settings at the client level or through Group Policy for managed devices.

Admin Checklist to Fix Pending Sync for Shared Libraries

Use the following checklist in order. Each step addresses one part of the pending sync problem. Apply the changes on each affected user device or deploy them centrally via Group Policy.

1. Check the current network speed
   Open a command prompt and run ping outlook.office365.com -n 10. Note the average round-trip time. If it exceeds 150 ms, the network is slow enough to trigger the throttling behavior. Run speedtest-cli or a browser-based speed test to confirm download speed is below 5 Mbps.
2. Increase the file scan timeout
   Open Registry Editor. Navigate to HKEY_CURRENT_USER\Software\Microsoft\OneDrive\Accounts\Business1. Create a new DWORD (32-bit) value named ThrottlingAutoDetectionDelay. Set the value to 120 decimal. This extends the scan timeout to 120 seconds. Restart OneDrive after making this change.
3. Remove the download bandwidth limit in OneDrive settings
   Right-click the OneDrive icon in the notification area. Select Settings. Go to the Sync and backup tab. Click Advanced settings. Under Download bandwidth limit, select Do not limit. Click OK. This removes the 1 Mbps throttle that keeps the sync pending.
4. Apply a Group Policy bandwidth limit for managed devices
   If you manage devices with Group Policy, download the OneDrive administrative template files. In the Group Policy Management Editor, go to Computer Configuration > Administrative Templates > OneDrive > Sync settings. Enable the policy Set maximum download throughput rate. Set the rate to a value that matches your network capacity, such as 5000 for 5 Mbps. Apply the policy and run gpupdate /force on client devices.
5. Pause and resume the shared library sync
   After applying the registry and bandwidth changes, right-click the OneDrive icon and select Pause syncing. Choose 2 hours. Then right-click again and select Resume syncing. This forces OneDrive to restart the scan with the new timeout and bandwidth settings.
6. Verify the sync status
   Open OneDrive and check the shared library. The pending status should change to syncing within two minutes. If it remains pending, repeat step 2 and increase the ThrottlingAutoDetectionDelay value to 180 decimal.

If Shared Library Sync Still Stays Pending

OneDrive reports a red circle with a white minus sign on the shared library

This icon means the library is not syncing at all. The cause is often a file path that exceeds the 400-character limit. Ask the user to rename the library or move files to a shorter path. Then pause and resume sync as described in step 5.

The sync seems to start but then reverts to pending

This pattern indicates the file scan timeout is still too short. Increase the ThrottlingAutoDetectionDelay registry value to 240 decimal. Also check that the user has the correct permissions for the shared library. If the user was recently added, wait 15 minutes for permissions to propagate.

Multiple shared libraries all show pending simultaneously

This points to a network-level issue rather than a single library. Check the corporate firewall or proxy for throttling of HTTPS traffic to sharepoint.com and all subdomains. Whitelist these endpoints and ensure TLS 1.2 is enabled. Then apply the bandwidth limit policy from step 4 to all clients.

OneDrive Sync Settings for Slow Networks: Default vs Recommended

Setting	Default Value	Recommended for Slow Networks
Download bandwidth limit	1 Mbps (automatic)	Do not limit or 5 Mbps via Group Policy
File scan timeout	30 seconds	120 seconds (registry)
Upload bandwidth limit	1 Mbps (automatic)	Do not limit
Sync concurrency	Automatic	No change needed

The default values are designed for typical office networks with at least 10 Mbps download speed. On slow networks below 5 Mbps, the defaults keep the sync in a pending state. The recommended settings remove the artificial throttle and extend the scan timeout so the sync engine can complete the initial handshake.

After applying the registry change and bandwidth setting from this checklist, shared library sync should move from pending to active within two minutes. If the problem persists, verify the network speed with a consistent ping and speed test. As an advanced step, you can deploy the registry value through Group Policy Preferences to all users who work on slow connections, ensuring the fix applies automatically without manual configuration on each device.