OneDrive File Issues

Fix OneNote Sync Error Despite Having Free OneDrive Storage

Camila Milosovich Oct 13, 2026 870 views

Question details

The user is experiencing a synchronization failure in OneNote accompanied by a 'no storage' error, despite having nearly 1 TB of available OneDrive cloud space.

How to Fix OneNote Sync Errors Despite Free OneDrive Storage

Product: Microsoft OneNote
Device & OS: not provided
Scenario: Attempting to sync local OneNote notebooks to a OneDrive account with sufficient cloud storage.
Observed behavior: OneNote fails to synchronize notebooks for an extended period, displaying an out-of-storage error (such as 0xE00015E0) even though the OneDrive account has plenty of free space available.

Before you start

Verify that your local computer has at least 5-10 GB of free hard drive space, as OneNote requires local disk space to cache and process notebooks before uploading them to the cloud.

Solution 1Recommended

Optimize OneNote Files and Clear Local Storage

This is the most common fix. The error often triggers because the local device lacks the hard drive space needed to build the sync cache, or the notebook cache has become too bloated.

OneNote uses a local cache to temporarily store edits before pushing them to OneDrive. If your local C: drive is nearly full, or if the notebook cache has grown uncontrollably, OneNote will report a 'storage full' error regardless of your cloud capacity.

Open Save & Backup settings

Launch Microsoft OneNote. Click on the 'File' tab in the top left corner, navigate to 'Options', and select 'Save & Backup' from the left-hand menu.

Optimize all files

Under the 'Optimizing files' section on the right, click the 'Optimize All Files Now' button. Wait for the process to complete, which compresses your local notebook cache.

Free up local disk space

Open Windows File Explorer and check the available space on your primary hard drive. Delete unnecessary files or empty the Recycle Bin to ensure you have ample free local storage.

Remove unnecessary backups

Still in the 'Save & Backup' menu, check your backup folder path. Navigate to that folder in File Explorer and delete old, outdated backup files that are consuming local space.

Optimize OneNote Files and Clear Local Storage

About Error Code 0xE00015E0: If you receive error code 0xE00015E0 specifically, it is a direct indication that your device does not have enough local space, or a particular notebook section is too large to sync.

Solution 2

Resolve Conflicting Notebook Sections

Conflicting notebook rules or corrupted sections can halt the synchronization process and generate false error messages.

Free Microsoft Office alternative

Switch to WPS Office for Seamless Cloud Syncing

If you frequently encounter syncing errors and bloated local cache issues with Microsoft Office, consider switching to WPS Office. It provides a lightweight, highly compatible alternative with smooth, built-in cloud synchronization.

1. Download and Install: Visit the official WPS website to download the free installation package and follow the quick setup wizard.
2. Sign In for Cloud Storage: Open WPS Office and sign in to activate your free WPS Cloud space for seamless document backups.
3. Edit and Sync Automatically: Open your existing Office documents in WPS. Changes are automatically saved and synced to the cloud without heavy local caching.

Fully compatible with Microsoft Office formats, including .docx, .xlsx, and .pptx.Lightweight software architecture that consumes significantly less local disk space.Built-in WPS Cloud integration that syncs your documents quickly and reliably.Free to use with a familiar interface, requiring zero learning curve to migrate.

microsoft office alternative - wps office

Frequently Asked Questions

Why does OneNote say my storage is full when my OneDrive is almost empty?

OneNote uses your computer's local hard drive to cache changes before uploading them to OneDrive. If your local device is out of space, OneNote will display a storage error, even if you have a terabyte of free cloud storage.

How do I force OneNote to sync immediately?

You can force a manual sync by right-clicking the name of your notebook in the OneNote interface and selecting 'Sync This Notebook Now', or by pressing the Shift + F9 shortcut keys.

Can a single OneNote notebook be too large to sync?

Yes. If a specific notebook or section contains too many large attachments, embedded PDFs, or high-resolution images, the local cache may fail to process the upload. Try splitting large notebooks into multiple smaller ones.

Where are OneNote local backups stored on Windows?

By default, local OneNote backups are stored in 'C:\Users\[YourUsername]\AppData\Local\Microsoft\OneNote'. Navigating to this folder and deleting outdated backups is a great way to free up local storage space for syncing.

Document & File Issues