OneDrive for Business shared library sync troubleshooting for large document libraries: stays pending

You have added a shared library in OneDrive for Business, but the sync status shows “Pending” and never completes. This problem is common when the library contains thousands of files or folders. The sync engine struggles to process the item metadata and file changes in large libraries, causing it to stay in a pending state indefinitely. This article explains the root cause, provides step-by-step fixes to resolve the pending status, and covers related failure patterns for large shared libraries.

Why OneDrive Sync Stays Pending on Large Shared Libraries

OneDrive for Business uses the same sync engine as SharePoint. When you sync a shared library with many items, the engine must download metadata for every file and folder in the library. If the library contains more than 30,000 items, the sync engine can stall while processing the metadata. The pending status indicates that the engine has started the sync but cannot complete the initial enumeration of all items.

The technical limit for a synced library is 300,000 items across all folders. However, performance degrades significantly above 100,000 items. The sync engine also checks for file version history, permissions, and custom metadata columns, all of which increase the processing time. When the engine hits a timeout while enumerating items, it displays “Pending” and retries repeatedly without making progress.

Another factor is the number of files open in Office applications. If many files in the library are open in Word, Excel, or PowerPoint, the sync engine waits for those files to be saved and closed before it can update the local copy. In large libraries, this can cause the pending state to persist for hours.

Steps to Resolve the Pending Sync Status for Large Shared Libraries

Before starting, ensure you have the latest version of OneDrive installed. Open OneDrive Settings > About OneDrive and verify the version number. Then follow these steps in order.

1. Pause sync for the shared library
   Right-click the OneDrive icon in the system tray. Select “Pause syncing” and choose 2 hours. This stops all sync activity and allows the engine to reset its internal state.
2. Stop syncing the library entirely
   Open OneDrive Settings > Account. Under “Choose folders,” find the shared library. Uncheck the library to remove it from the sync list. Click OK. Wait for the local files to be removed — this can take several minutes for large libraries.
3. Restart the OneDrive sync engine
   Press Ctrl+Alt+Delete and open Task Manager. Find “Microsoft OneDrive” in the Processes tab. Right-click it and select “End task.” Then launch OneDrive from the Start menu. This clears any stuck processes.
4. Re-add the library with selective folders
   Open OneDrive Settings > Account > Choose folders. Check the shared library again. In the folder tree that appears, uncheck all folders except the ones you need immediately. Click OK. OneDrive will sync only those folders, reducing the initial metadata load.
5. Wait for the sync to initialize
   OneDrive will show “Processing changes” for the selected folders. This is normal. Do not pause or stop sync during this phase. The pending status should change to “Up to date” within 15 minutes for folders under 10,000 items.
6. Add additional folders after sync completes
   Once the initial folders are synced, return to OneDrive Settings > Account > Choose folders. Check additional folders one at a time. Let each folder sync fully before adding the next. This prevents the engine from being overwhelmed.

If the Pending Status Returns After Adding More Folders

If you add a folder with more than 5,000 items and the pending status reappears, repeat steps 1 through 3. Then add that folder alone. If the folder itself has more than 30,000 items, consider syncing subfolders individually instead of the parent folder.

If OneDrive Still Stays Pending After the Main Fix

OneDrive Shows “Pending” for More Than 24 Hours

This indicates a deeper issue with the library structure. Open the library in a web browser. Check the total item count by clicking the gear icon > Library settings > under “General settings,” view the item count. If the count exceeds 300,000, the library exceeds the sync limit. You must split the library into smaller sub-libraries or use SharePoint search instead of syncing.

To split a library, create a new document library in the same SharePoint site. Move a portion of the files into the new library using SharePoint’s Move To command. Then sync the new library separately.

OneDrive Sync Engine Uses Excessive CPU or Memory

When the sync engine is stuck on a large library, it can consume 100% CPU or gigabytes of RAM. Open Task Manager and check the OneDrive process. If CPU usage stays above 50% for more than 10 minutes, reset OneDrive completely. Open Windows Settings > Apps > Installed apps. Find Microsoft OneDrive, click the three dots, and select “Advanced options.” Click “Reset.” This clears the sync cache without deleting your local files. After the reset, re-add the shared library using the selective folder method from step 4.

OneDrive Sync Stays Pending on Network Drives or VPN

If you are connected through a VPN, the sync engine may time out while enumerating items. Disconnect from the VPN temporarily. Open OneDrive Settings > Network and set the upload and download rate limit to 50% of available bandwidth. Reconnect the VPN after the initial sync completes. If the pending status returns, use the selective folder method to sync only critical folders.

Files-On-Demand vs Always Keep on This Device: Key Differences for Large Libraries

Item	Files-On-Demand	Always Keep on This Device
Description	Files appear online-only until opened	Files are downloaded and kept locally
Initial sync time	Fast — only metadata is downloaded	Slow — all file contents are downloaded
Disk space usage	Minimal — only thumbnails and metadata	Full file sizes consume local storage
Best for large libraries	Yes — avoids full download of thousands of files	No — causes pending state on libraries over 30,000 items
How to set	OneDrive Settings > Sync and backup > Files-On-Demand	Right-click folder > Always keep on this device

For shared libraries with more than 10,000 items, Files-On-Demand is the only reliable option. When you use “Always keep on this device,” OneDrive tries to download every file, which causes the pending state to persist for days. Switch to Files-On-Demand before adding a large library.

You can enable Files-On-Demand in OneDrive Settings > Sync and backup. Check the box “Save space and download files as you use them.” After enabling, right-click any folder in the synced library and select “Free up space” to convert downloaded files back to online-only.

Now you can resolve the pending sync status for large shared libraries by pausing, removing, and re-adding the library with selective folders. Use Files-On-Demand to avoid future pending problems. For libraries over 300,000 items, split the library in SharePoint before syncing. An advanced tip: use the SharePoint Migration Tool to move large libraries to a separate site collection, which bypasses the sync engine entirely for archival data.