OneDrive File Issues

Fix Files Missing When Copying from External Drive to OneDrive

Maira Mehtab Sep 24, 2026 869 views

Question details

The user is experiencing an issue where copying folders from an external hard drive to OneDrive results in empty folders, missing files, and unexpectedly low storage usage.

Product: Microsoft OneDrive
Device & OS: not provided
Scenario: Copying bulk files and folders from an external hard drive to the local OneDrive directory for cloud backup.
Observed behavior: Folders appear in OneDrive, but the actual files inside them are missing. As a result, the reported storage usage remains significantly lower than the size of the original data on the external drive.

Before you start

Ensure you have a stable internet connection and that the external hard drive remains securely connected to your computer throughout the entire transfer process.

Solution 1Recommended

Copy Files in Smaller Batches and Verify Sync Status

Transferring a massive amount of data at once can overwhelm the sync client. Breaking the transfer into smaller chunks ensures files are properly uploaded.

When migrating large directories from an external drive, copying everything at once might cause OneDrive to rapidly create the folder structures before stalling on the actual file uploads. Managing the transfer manually helps prevent synchronization timeouts.

Check OneDrive Status

Click the OneDrive cloud icon in your system tray (Windows) or menu bar (Mac) to ensure the application is running and actively syncing without any reported errors.

Transfer Data in Batches

Instead of dragging the entire external drive contents at once, select a few folders at a time and copy them directly into the local OneDrive folder.

Wait for Synchronization

Keep your computer awake and the external drive plugged in until the OneDrive icon displays an 'Up to date' status or a solid green checkmark appears next to the newly copied files.

Verify Files Online

Log in to the OneDrive web interface via your browser to confirm that the files themselves, not just the parent folders, are fully visible and occupying the correct amount of cloud storage space.

Unsupported File Names: Check if your files contain unsupported characters (such as <, >, :, ", |, ?, *, /, \) which can completely prevent OneDrive from syncing specific items.

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Frequently Asked Questions

Why does OneDrive show my folders but not the files inside them?

This typically happens when the synchronization process is interrupted, the transfer batch is too large, or certain files contain unsupported characters. OneDrive quickly recreates the directory structure but requires significantly more time to upload the actual file data.

How can I check if my external drive files are actually backed up on OneDrive?

The most reliable method is to log into the OneDrive website using your web browser. If the files are visible there, show the correct file size, and can be opened or downloaded, they have successfully synced to the cloud.

Does copying files from an external drive to OneDrive move them or duplicate them?

If you drag and drop files from an external drive to your local OneDrive folder on a Windows PC or Mac, it copies (duplicates) them by default. This means your original files safely remain on your external drive.

What are the restricted characters for OneDrive file names?

Files will not sync if their names contain certain characters such as asterisks (*), question marks (?), quotation marks ("), or slashes (\ /). You must rename these files on your external drive to remove the invalid characters before copying them to the OneDrive folder.

Document & File Issues