Large File Upload Fails Near Completion: OneDrive for Business Fix

You are uploading a large file to OneDrive for Business. The upload progresses to 90 percent or higher and then fails without a clear error message. This failure near completion is often caused by a network interruption, a file size limit, or a timeout setting in your browser or sync client. This article explains the root causes of this problem and provides specific steps to upload large files successfully.

Why Large OneDrive Uploads Fail Near the End

Uploading a large file to OneDrive for Business involves splitting the file into chunks and sending them sequentially. When the upload reaches the final chunk, the server must reassemble the file and verify its integrity. A failure near completion typically occurs because one of these conditions is not met:

File Size and Type Restrictions

OneDrive for Business has a per-file upload limit of 250 GB. Files larger than this cannot be uploaded. Additionally, some file types are blocked by default in SharePoint and OneDrive, such as executable files (.exe, .msi) and script files (.vbs, .ps1). If you try to upload a blocked file type, the upload will fail regardless of size.

Network Timeout and Browser Session Limits

When you upload through a web browser, the browser has a session timeout and a maximum request duration. For a file over 100 MB, the upload may take longer than the browser timeout, causing the connection to drop. Corporate networks with proxy servers or VPNs may add additional timeout limits that cut the upload short.

OneDrive Sync Client Behavior

The OneDrive sync client for Windows uses a different upload mechanism than the browser. It maintains a persistent connection and can resume interrupted uploads. However, if the sync client is paused, if the local file is locked by another application, or if the disk runs out of space, the upload will fail near completion.

Steps to Upload Large Files Successfully

Follow these steps in order. Start with the method most likely to resolve the issue for your scenario.

Method 1: Use the OneDrive Desktop Sync Client

1. Install or open the OneDrive sync client
   On Windows 10 or Windows 11, click the OneDrive cloud icon in the notification area. If you do not see it, search for “OneDrive” in the Start menu and open the desktop app.
2. Move the large file into a synced folder
   Copy the file into any folder that is synced to OneDrive for Business, such as the OneDrive folder in File Explorer. The sync client starts uploading automatically.
3. Monitor the upload status
   Hover over the OneDrive icon to see the upload progress. Wait until the file shows a green check mark indicating successful sync.
4. If the upload fails again, check the sync client logs
   Open OneDrive settings by right-clicking the cloud icon and selecting Settings. Go to the Sync and backup tab and click Advanced settings. Under Sync activity, review any errors listed for the file.

Method 2: Upload via Microsoft Edge or Chrome with Resume Support

1. Open the OneDrive website in a modern browser
   Go to onedrive.com and sign in with your work or school account. Use Microsoft Edge or Google Chrome for the best resume support.
2. Drag the file into the browser window
   Drag and drop the large file directly onto the OneDrive web page. The browser uploads the file in chunks and can resume if the connection drops.
3. Do not close the browser tab during upload
   Keep the tab open and active. If your computer goes to sleep or the network disconnects, the upload pauses. When you reconnect, it resumes from the last completed chunk.

Method 3: Split the File into Smaller Parts

1. Use a compression tool to split the file
   Right-click the file in File Explorer, select Send to > Compressed (zipped) folder. For files larger than 10 GB, use 7-Zip or WinRAR to create multiple archive parts of 1 GB each.
2. Upload each part separately
   Upload the archive parts one at a time through the OneDrive sync client or the web browser. Each part is small enough to avoid timeout issues.
3. Reassemble the file on the destination computer
   After all parts are uploaded, download them and use the same compression tool to extract the original file.

Method 4: Adjust Network and Proxy Settings

1. Disable VPN during upload
   If you use a VPN, disconnect it temporarily. VPNs add latency and may enforce shorter timeouts that cause uploads to fail near completion.
2. Switch to a wired Ethernet connection
   Use an Ethernet cable instead of Wi-Fi to reduce packet loss and signal drops during long uploads.
3. Check proxy server timeout settings
   Contact your IT administrator and ask them to increase the proxy timeout to at least 30 minutes for the OneDrive domain and all subdomains.

If OneDrive Still Fails After the Main Fix

OneDrive Shows “Upload blocked” for a specific file type

OneDrive for Business blocks certain file extensions by default. If your file has an extension like .exe, .msi, .bat, .cmd, .vbs, .ps1, or .js, the upload will fail near completion because the server rejects the file type. To fix this, compress the file into a .zip archive before uploading. The .zip extension is allowed.

The file is larger than 250 GB

OneDrive for Business has a maximum file size limit of 250 GB. Files exceeding this limit cannot be uploaded, even with the desktop sync client. Use a compression tool to split the file into multiple archives under 250 GB each, or store the data on a local drive and use a different storage service.

The sync client shows “Changes not syncing” with no progress

This often happens when the file is locked by another application. Close all programs that might be using the file, such as Microsoft Excel or Adobe Photoshop. Then right-click the OneDrive icon and select Resume sync. If the problem persists, restart the OneDrive sync client by right-clicking the icon and selecting Close OneDrive, then reopening it from the Start menu.

Desktop Sync Client vs Web Browser Upload: Key Differences

Item	OneDrive Desktop Sync Client	Web Browser Upload
Resume capability	Automatic resume after interruption	Resume only if browser supports chunked upload (Edge, Chrome)
File size limit	250 GB per file	250 GB per file (browser may impose lower practical limit)
Network timeout	No browser timeout; uses persistent connection	Subject to browser and proxy session timeouts
File type blocking	Blocked types are rejected during sync	Blocked types are rejected at upload start
Best use case	Files over 100 MB, frequent uploads, resume needed	Small files under 100 MB, one-time uploads

You can now upload large files to OneDrive for Business without failures near completion. Start with the desktop sync client for the most reliable resume behavior. If you frequently work with files over 1 GB, compress them into smaller archives before uploading. As an advanced tip, configure the OneDrive sync client to throttle upload speed during working hours by going to OneDrive settings > Sync and backup > Advanced settings > Upload rate limit.