Any news from Microsoft about the incorrectly sent "Your Microsoft storage is almost full" E-Mails...?

Question

It appears that 5 days ago, Microsoft sent out E-Mails to an unknown number of people stating that their storage is over 80% full. Logging into my account showed me I was using 0.1% of my total space. A quick look online showed me a number of people on Reddit, Twitter, Facebook and even people on this website had received the same E-Mail.

I just want to clarify, I actually work in IT and a quick check tells me the E-Mail I got 100% came from Microsoft. The DKIM, SPF and DMARC are all legit. All the links on the E-Mail point to the "..microsoft.com" domain name. The headers all check out etc etc.

As a system administrator, I have had several calls from people in regards to this after they believed they were hacked. Microsoft need to look into this to find out why the E-Mail was sent in the first place.

Answer 1

Hello

I am seeing a lot of people receiving this email too. I believe the email is also legitimately from Microsoft, but I suspect that the email was fired by mistake.

As of now, there's no official information from Microsoft to clarify this email. This is community forum, so there's no way any investigation can be initiated from here. I would recommend that you raise it via official support channel. If you are a business user, you can raise it via Support in your Admin Center.

Answer 2

Microsoft has not documented any broad incident of “incorrectly sent” storage‑almost‑full emails in the provided material. However, the current Outlook.com and Microsoft storage documentation clarifies how these quota notifications are supposed to work and why they can appear even when Outlook.com mailbox usage looks low:

1. Unified Microsoft storage vs. mailbox storage
   The warning emails are based on Microsoft unified cloud storage, not just Outlook.com mailbox usage. Unified storage includes OneDrive files, Outlook.com attachments, and other Microsoft 365 data. A mailbox showing very low usage (for example, 0.1% of its email quota) can still trigger a warning if the overall Microsoft storage quota is near or over its limit.
2. Effect of exceeding Microsoft storage
   When the unified storage quota is exceeded:
   • Uploading, editing, or syncing new files to OneDrive is blocked; existing files become read‑only.
   • Sending or receiving email in Outlook.com is blocked, even if the mailbox itself is under its email storage quota.
   • Teams messages with attachments cannot be sent or received.
   • After 6 months over quota, OneDrive content may be deleted.
3. “Microsoft Unified Storage is full” behavior
   The “Microsoft Unified Storage is full” message explicitly refers to the unified cloud storage quota, not just Outlook.com mailbox size. The documentation reiterates that:
   • Exceeding Microsoft storage blocks Outlook.com mail flow even if email storage is not exceeded.
   • Exceeding email storage alone also blocks Outlook.com mail flow.
4. What users are expected to do
   Official guidance for users who receive these warnings is to:
   • Check unified storage usage and either buy more storage or free up storage space (for example, by deleting large OneDrive files or Outlook.com attachments) to get back under quota.
   • For free users, purchase a subscription to increase quota or free up space.
   • For Microsoft 365 subscribers, note that consumer mailbox limits are capped at 100 GB; if that limit is reached, space must be freed.
5. No published incident about a false‑positive campaign
   The context includes:
   • A documented Outlook.com incident about a 0/0 GB storage display bug that affected sending/receiving but has been marked as fixed.
   • General storage‑quota behavior and FAQs.
     None of these describe a Microsoft‑acknowledged, large‑scale erroneous email campaign where storage‑almost‑full notifications were sent to accounts that were not near their unified storage quota.

For users or admins seeing these emails while believing usage is low, the documented next step is to verify total Microsoft unified storage (not just Outlook.com mailbox usage) and manage or purchase storage accordingly.

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References:

• Fixes or workarounds for recent issues on Outlook.com
• Microsoft storage quotas
• Storage limits in Outlook.com
• Microsoft storage FAQs