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Using OneDrive desktop application on a large SharePoint document library which have around half-million items is not syncing

john john Pter 1,550 Reputation points
2026-05-21T11:10:46.4233333+00:00

Hi,

we have a SharePoint document library with around 500,000 files and folders, users using the browser to access those items are not facing issue, but user who use onedrive desktop application are having lot of sync issue, what is the reason? and how we can overcome this?

Thanks

Microsoft 365 and Office | SharePoint | Development
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Gabriel-N 17,785 Reputation points Microsoft External Staff Moderator
2026-05-21T12:20:52.8366667+00:00

Hello @john john Pter

First, I recommend reviewing the AI-generated response on your post, as it already provides some helpful insights that align closely with what you observed.

In summary, Microsoft guidance recommends keeping the total number of synced items under approximately 300,000 for optimal performance. When a library grows beyond that threshold, as in your case with around 500,000 items, the OneDrive desktop application can begin to experience the types of sync issues you are seeing. This happens because the sync client needs to build and maintain a local index (and in many cases a two-way replica) of the library on each device, which becomes very resource-intensive in terms of CPU, memory, disk, and network usage.

In simpler terms, the issue is not with SharePoint itself, which can handle significantly larger libraries, but with the scalability of the desktop sync client when dealing with very large numbers of files.

As immediate steps, I would suggest enabling Files On-Demand (if not already in use) so that most files remain in the cloud and are only downloaded as needed. It is also advisable to reduce the sync scope by selecting only the specific folders users require instead of syncing the entire library.

For a longer-term solution, it would be beneficial to review your overall library structure and consider splitting the content into smaller, more manageable libraries, for example by department, project, or time period. Please consider this approach if it fits your environment since this might help ensure each sync scope stays within a range where the client can operate reliably.

As a note, Microsoft has started introducing improvements that support higher sync limits in certain scenarios, but a library of this size is still considered large, so applying selective sync and optimizing the structure remains important for a stable experience.

For more in-depth and targeted guidance based on your specific environment (such as tenant-level diagnostics or log analysis), you may need to open a support request with Microsoft Support. As this is a user-to-user forum, moderators like us do not have access to backend tools or internal diagnostics to investigate further.

Hope this information helps.

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  1. AI answer

    2026-05-21T11:11:15.6433333+00:00

    The sync issues occur because the SharePoint/OneDrive sync client has practical limits on how many items can be synchronized, and a library with ~500,000 items exceeds those limits.

    From the documented limits:

    • For SharePoint/OneDrive sync, performance issues occur when there are more than 300,000 items across cloud storage, even if not all items are synced.
    • For SharePoint-specific sync, if there are more than 100,000 files, sync can take a very long time and appear stuck (for example, showing “Processing 0KB of xMB”).
    • There are also limits on items that can be synced or copied at once and on file/path lengths; exceeding these can cause sync to never complete.

    Because the browser view is not subject to the same local sync constraints, users can browse the 500,000 items in the web UI without issues, while the OneDrive desktop client struggles or fails.

    To mitigate or overcome this:

    1. Reduce the number of items being synced to each client
      • Use selective sync so that users only sync the folders they actually need from the large library. Guidance is to keep total synced items well below 300,000 across OneDrive/SharePoint content for best performance.
      • For SharePoint libraries, if the OneDrive folder “Contains” more than 100,000 items, consider choosing fewer OneDrive/SharePoint folders to sync to that computer.
    2. Restructure or split the library
      • Where possible, split the 500,000-item library into multiple libraries or reorganize content so that any single synced scope (library or selected folders) stays under the recommended item limits.
    3. Use the browser or other non-sync access paths for very large libraries
      • For very large document libraries, rely primarily on the browser experience instead of trying to sync the entire library to every client.
    4. Check for other sync blockers
      • Ensure files do not violate restrictions such as path length limits, invalid characters, or unsupported file types, as these can also cause sync to hang or never finish.

    If sync is already in progress and appears stuck, pausing and resuming sync can sometimes help, but the fundamental fix is to bring the number of synced items within the documented limits.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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