"OneDrive is using too much space" can mean two different things: your local hard drive is filling up because of OneDrive, or your internet connection is being saturated by OneDrive's syncing activity. Worth being clear on which one you're actually dealing with.

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If it's local disk space

This happens when too many files are set to "Always keep on this device," or Files On-Demand is disabled entirely, meaning everything in your OneDrive is being stored fully on your local drive.

Fix: enable Files On-Demand if it's off

  1. Click the OneDrive icon in the system tray → Help & Settings → Settings
  2. Go to the Settings tab and confirm "Save space and download files as you use them" is checked

Fix: free up space for files you don't need locally

  1. In File Explorer, navigate to your OneDrive folder
  2. Find files/folders you don't need available offline
  3. Right-click and select "Free up space" — this converts them back to cloud-only placeholders, removing them from local storage while keeping them fully accessible in OneDrive (they'll just re-download on demand when opened)

If it's bandwidth

If OneDrive syncing is noticeably slowing down your internet connection — video calls stuttering, web pages loading slowly — while a large sync is happening, you can limit how much bandwidth OneDrive is allowed to use:

  1. Click the OneDrive icon → Help & Settings → Settings
  2. Go to the Network tab
  3. Under "Upload rate" and "Download rate," you can set a specific limit (in Kbps) instead of "Don't limit," which lets OneDrive use as much bandwidth as available
  4. Setting a reasonable cap here prevents OneDrive from competing too aggressively with other activities like video calls

If a large initial sync is the cause

If you've just set up OneDrive on a new computer, or recently added a large number of files, an unusually large amount of bandwidth and disk usage in the following hours or days is expected and temporary — the initial sync of an entire OneDrive library can be substantial. This should settle down to minimal background activity once everything has fully synced for the first time.

Check overall account storage too

Separate from local device storage, your actual OneDrive cloud storage allocation (the total space in your Microsoft 365 plan) is worth checking if you're getting "running low on storage" notifications:

  1. Go to onedrive.com and sign in
  2. Check your storage usage in the sidebar
  3. If you're near your plan's limit, delete files you genuinely don't need, or consider whether your current plan's storage allocation still fits your needs