OneDrive File Issues

How to Fix OneDrive Crashes When Copying Large Files to SharePoint

Aamir Naveed Akram Sep 25, 2026 868 views

Question details

The user needs to resolve frequent application crashes occurring while attempting to synchronize a massive batch of files to SharePoint.

How to Fix OneDrive Crashes When Copying Large Files to SharePoint

Product: OneDrive
Device & OS: not provided
Scenario: Synchronizing approximately 250,000 Office and PDF files to a SharePoint document library.
Observed behavior: OneDrive or File Explorer crashes during the synchronization process, occasionally displaying an ntmartha.dll error.

Before you start

Pause your current OneDrive synchronization process to prevent further crashes or partial file transfers while you troubleshoot the setup.

Solution 1Recommended

Remove Conflicting SharePoint Folder Shortcuts

Use this solution to eliminate synchronization conflicts caused by syncing a shortcut and the direct library simultaneously.

OneDrive does not support syncing a SharePoint folder shortcut while also syncing the exact same document library directly. This duplication causes synchronization loops and failures that lead to application crashes.

Locate the shortcut

Open your local OneDrive folder or log in to the OneDrive web interface to identify any SharePoint folder shortcuts you have created.

Delete the shortcut

Right-click the shortcut in File Explorer and select 'Remove', or delete it directly from the OneDrive website.

Sync the library directly

Navigate to the SharePoint document library in your web browser and click the 'Sync' button to connect it directly to your OneDrive client without using shortcuts.

Test in smaller batches

Instead of synchronizing all 250,000 files at once, move the files into the local sync folder in smaller, manageable batches to prevent memory overloads.

Remove Conflicting SharePoint Folder Shortcuts

Sync Conflict Resolved: Removing duplicate sync paths often immediately resolves File Explorer and OneDrive stability issues during large transfers.

Solution 2

Investigate the ntmartha.dll Fault

Use this solution if OneDrive continues to crash after fixing sync conflicts and transferring files in smaller batches.

Free Microsoft Office alternative

Manage Office Documents Seamlessly with WPS Office

While resolving OneDrive and SharePoint synchronization issues, you can rely on WPS Office for a lightweight and highly efficient document management experience. WPS Office is a free alternative to Microsoft Office that easily handles large batches of documents without straining your system resources.

1. Download WPS Office: Visit the official WPS Office website and download the free installation package.
2. Install the application: Run the installer and follow the on-screen instructions to set up the suite on your device.
3. Open your files: Launch WPS Office and open your synchronized Office and PDF files directly from your local drive.

Fully compatible with Microsoft Office formats including DOCX, XLSX, and PPTX.Lightweight application design ensures smooth performance when opening large files.Built-in PDF editing tools perfectly complement your PDF document workflows.Familiar tabbed user interface makes migrating from other office suites completely seamless.

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Frequently Asked Questions

Can I sync a SharePoint shortcut and the document library at the same time?

No. OneDrive does not support syncing both a SharePoint folder shortcut and the same document library directly. Doing so creates conflicts that result in synchronization failures and application crashes.

Why does syncing 250,000 files cause File Explorer to crash?

Processing an excessively large number of files simultaneously can overload OneDrive's caching capacity and system memory, leading to instability in File Explorer and the OneDrive client. It is highly recommended to transfer massive amounts of files in smaller batches.

What does the ntmartha.dll error mean during file synchronization?

The ntmartha.dll error indicates a system-level fault, often related to how Windows processes file paths and permissions. When it appears during large OneDrive transfers, it usually requires further investigation of Windows crash logs by Microsoft Support.

Document & File Issues