If you're using OneNote and encounter the error message "You're out of disk space" or similar notifications like "You've run out of space" or "Not enough space", it can be frustrating. This issue can prevent you from syncing your notes or adding new content. Fortunately, there are several methods to resolve this problem and free up space for your OneNote notebooks.

Fixing the "You're out of disk space" error in OneNote

Verify Available Storage Space

The first step is to check if you're actually running low on storage space, either on your local device or in the cloud service where your notebooks are stored.

Check OneDrive or SharePoint Storage

If your OneNote notebooks are stored on OneDrive or SharePoint, you might have exceeded your storage quota.

  1. Open your web browser and navigate to OneDrive.
  1. Sign in to your Microsoft account.
  1. Look for the storage usage indicator to see how much space you've used.
  2. If you're low on space, consider deleting unnecessary files or upgrading your storage plan.
OneDrive storage usage indicator

Alternatively, you can empty the OneDrive Recycle Bin to free up space:

  1. In OneDrive, click on the Recycle bin in the left sidebar.
  1. Select all files and folders and click Delete to permanently delete the files.

Check Local Disk Space

If your notebooks are stored locally or you have limited disk space on your device:

  1. On your computer, open File Explorer.
  1. Right-click on your main drive (usually C:) and select Properties.
  1. Review the available free space. If it's low, consider deleting unnecessary files or using disk cleanup tools.
Disk properties showing available space

Optimize OneNote Notebooks

Optimizing your notebooks can reduce their size by removing redundant data and compressing files.

  1. Open the OneNote application on your computer.
  2. Click on File in the top menu.
  1. Select Options to open the OneNote options dialog.
  1. In the left sidebar, choose Save & Backup.
  1. Under the Optimize Files section, click on Optimize All Files Now.
  1. Wait for the optimization process to complete, then click OK.

Delete Existing Backups

OneNote automatically creates backups of your notebooks, which can consume significant disk space over time.

  1. Press Win+R to open the Run dialog box.
  1. Type %localappdata% and press Enter.
  1. Navigate to the following folder: Microsoft\OneNote\16.0\Backup
  1. If you find any unnecessary backup files, delete them to free up space.
  2. Restart the OneNote application.
OneNote backup folder

Clear OneNote Cache

Clearing the OneNote cache can resolve issues caused by corrupted or outdated cache files.

  1. Close OneNote if it's running.
  2. Open File Explorer.
  3. Navigate to the following folder (replace <user> with your username): C:\Users\\AppData\Local\Microsoft\OneNote\16.0
  1. Locate the folder named Cache.
  1. Right-click on the Cache folder and select Delete.
  1. Restart OneNote to allow it to recreate the cache folder.
Deleting OneNote cache folder

By following these steps, you should be able to resolve the "You're out of disk space" error in OneNote and continue syncing and using your notebooks without interruption.