Storage Issue

Question

cleaned almost all my emails with big attachments, but it still shows 5.1GB. What could be the problem?

Answer 1

Hi,

Do you currently have a Microsoft 365 or Microsoft 365 Basic subscription that provides additional storage for your email account?

After deleting emails, especially those with large attachments, the storage usage shown in Outlook.com may not update immediately. In most cases, it can take up to 72 hours for the system to recalculate and reflect the new storage amount.

During this time, the storage indicator may still show the previous usage even though the emails have already been removed. Once the recalculation completes, the storage should update automatically.

Answer 2

In Outlook.com, the reported 5.1 GB usually means either:

1. Mailbox folders still contain data that counts toward the quota
2. Microsoft cloud (OneDrive + Outlook attachments) storage is over quota, even if email folders look clean

Check both mailbox storage and unified Microsoft storage.

1. Verify mailbox folder usage

• In Outlook.com, open Settings and search for Storage, or go to Settings > Account > Storage.
• Under Email storage, expand the section to see how much space each folder uses.
• Use the options shown there to permanently delete all items (or items older than 3, 6, or 12 months) in large folders.
• Make sure to:
  • Empty Deleted Items (it counts against the quota until emptied).
  • Empty Junk Email (items are auto-deleted after 30 days, but can still be taking space now).

2. Remove large messages with attachments

• From the same Storage page, review folders sorted by size and delete remaining large messages with attachments.
• After deleting, also clear Deleted Items so the space is actually freed.

3. Check if Microsoft Unified Storage is full If a “Microsoft Unified Storage is full” or similar message appears, the issue is cloud storage, not just mailbox folders:

• Outlook.com email storage (15 GB free) is separate from Microsoft cloud storage (5 GB free shared across OneDrive files, Outlook.com attachments, and Microsoft 365 apps).
• If the 5 GB cloud storage is exceeded, Outlook.com may block sending/receiving even if mailbox usage looks low.
• To get back under quota, either:
  • Free up cloud storage (delete files/attachments from OneDrive/Outlook.com using the storage cleanup link), or
  • Buy a Microsoft 365 subscription to increase storage.

If, after cleaning folders and Deleted Items, the storage still shows 5.1 GB, the most likely cause is that Microsoft cloud storage (OneDrive + attachments) is still over the 5 GB limit rather than the mailbox folders themselves.

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References:

• What is Microsoft cloud storage?
• Storage limits in Outlook.com
• Mailbox storage limits in Outlook
• Reminder: Microsoft storage limit exceeded - Microsoft Q&A
• storage exceeded in outlook after purchasing MS 365 subscription - Microsoft Q&A