Phantom storage - Outlook is not allowing emails to be sent or received due to full storage, when in reality I am only using 168KB

Question

I have this issue in which my Outlook/Onedrive are unable to be used, claiming that the storage is full, while its empty, and doesn't even specify what is taking up so much space. Is there any way this can be fixed?

Answer 1

Hi Henrique Cookies,

The 9.3 GB / 5 GB shown under Outlook > Settings > Account > Storage refers to Microsoft cloud storage (OneDrive + Outlook attachments + other Microsoft services). When this unified storage is over quota, Outlook.com can block sending and receiving email, even if the mailbox itself is nearly empty. In your screenshot, the mailbox usage still shows less than 0.1 GB out of 15 GB, which explains why it feels like “phantom” storage.

To resolve this, please try the following in order:

1). Check OneDrive storage on the web

Go to OneDrive > Settings > Manage storage, look for large files, and empty the Recycle Bin. Be sure to also empty the second‑stage recycle bin, as items there can still count toward storage until permanently removed.

2). Confirm storage totals in Outlook.com

Go to Outlook.com > Settings > Account > Storage and compare the usage shown there.

3). Verify account consistency

Make sure both OneDrive and Outlook are signed in with the same Microsoft account.

4). Refresh sync if applicable

• If you use the OneDrive desktop app: click the OneDrive cloud icon > Settings > Account > Unlink this PC, then sign in again.
• If you’re using Outlook in a browser: sign out, clear the browser cache for Microsoft sites, then sign back in.

5). Allow time for updates

If files or attachments were deleted recently, allow some time for the storage totals to refresh across Microsoft services.

If the storage still shows as full after these steps, especially if the Microsoft storage page shows little or no usage. The storage total may not have refreshed correctly on the account side. In that case, Microsoft Support can help reset or refresh the storage calculation.

If you see a warning message when sending or receiving mail, please share the exact wording, as that can help narrow things down further.

Please let me know if this proves useful to you, or if you would like assistance in navigating Microsoft's support channel.

I'm looking forward to your reply.

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Answer 2

Outlook.com is blocking mail because the Microsoft unified cloud storage for the account (OneDrive + Outlook.com + other Microsoft services) is over quota, even though the mailbox itself is almost empty.

When Microsoft storage is exceeded:

• Sending and receiving email in Outlook.com is disabled, even if email storage is far below its limit.
• OneDrive becomes read‑only and new files cannot be uploaded.

The storage bar at the top of the screenshot (9.3 GB used of 5 GB) is the unified Microsoft storage, not the mailbox. To restore mail flow, the account must be brought back under the Microsoft storage quota. Options are:

1. Free up Microsoft storage
   • Sign in to the Microsoft account and delete or move files from OneDrive until the “Total used” value is below the quota.
   • Also check for large items such as photos, videos, or shared folders that count against the quota.
2. Purchase more storage
   • If using the free tier, buy a Microsoft 365 subscription or additional storage to increase the quota, then wait for the change to apply.

Once the unified storage usage is below the limit (or the quota is increased), Outlook.com will automatically allow sending and receiving email again.

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References:

• Storage limits in Outlook.com
• Microsoft storage FAQs
• My OneDrive says it's full