I've received a "Your mailbox is almost full" email on an Outlook account that doesn't appear to be full

Question

The message appears to be from ******@NETORGFT9409064.onmicrosoft.com. The mailbox that it references is an email address that I use, and it shows that the mailbox is 1.8 GB out of 1.9 GB available. However, when I look in my desktop Outlook at the email folder size, it is under 900 MB. When I look on the mail host's site (GoDaddy) but it doesn't seem to be anywhere near full, and in any case, that email account has 10 GB assigned.

I can't detect anything wanky in the full headers. There are only two links in the email. One is to send email to my account, and the other appears to be a legitimate Microsoft help topic which is addressed in the Q&A item https://answers.microsoft.com/en-us/windows/forum/all/i-am-receiving-warnings-that-my-mailbox-is-nearly/91d526c8-360e-4b57-83f5-5f2b1120d346.

So it doesn't look like spam/phishing, but it doesn't appear to be actionable either.

Any thoughts/guidance/suggestions welcome.

Answer 1

Hi @Eddi-Wan

Thanks so much for reaching out about that confusing "mailbox almost full" warning. I completely understand how frustrating it is when these alerts pop up, especially when your desktop Outlook and GoDaddy seem perfectly in order. You're definitely not alone in finding these puzzling, and I'm here to help you get to the bottom of it. 

From what you've shared, this alert is actually coming from an Exchange Online mailbox within your Microsoft 365 tenant (that's what the "@NETORGFT9409064.onmicrosoft.com" address indicates), not your GoDaddy mail account directly. This is why you're seeing different storage numbers: 

• Outlook on your desktop (900 MB): This shows a local file size, which often doesn't reflect the full mailbox size on the server. 
• GoDaddy mailbox (10 GB): That’s your full mailbox quota through GoDaddy, but your Microsoft 365 service likely has a separate, smaller quota set (such as the 1.9 GB seen in the warning message). 

So, the warning is about your mailbox size within that Microsoft environment. Let's look at the most effective ways to check your usage and free up space, focusing on the server-side data: 

Check & Clean Up Directly in Outlook on the Web 

This is the most accurate way to see your real-time mailbox size on the Microsoft server: 

• Go to outlook.office.com, go to Settings > Account > Storage. This shows your exact usage. 
• To clean up: Use the options here to empty Deleted Items and Junk Email. Also, sort your folders (like Inbox, Sent Items) by Size (largest on top) and delete any large emails or attachments you no longer need. Remember to empty Deleted Items again afterward. 

Use the Mailbox Cleanup Tool in Desktop Outlook 

• In your Outlook desktop app, go to File > Tools > Mailbox Cleanup. 
• Click View Mailbox Size to see folder usage. 
• Use "Find items larger than" or "Find items older than" to locate emails to delete. 
• Right-click your Deleted Items folder and select Empty Folder. 
• On the Folder tab, click Recover Deleted Items, then permanently delete everything there. 

For more details on using this tool, you can refer to Microsoft's support article: Manage my mailbox size in Outlook 

I hope this helps clarify why you're receiving those messages and provides a clear path forward. If anything, still seems unclear or you'd like help going through any of the steps, please feel free to reach out—I'm here to assist however I can.

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