From Microsoft Corporation
MC214532, Stay Informed, Published date: May 28, 2020
Whenever someone has used 90% or more of their inbox capacity, Outlook on the web will display a notification until the user reduces stored messages to below 90% of inbox capacity.
This message is associated with Microsoft 365 Roadmap ID 64275.
When this will happen
- We will begin rolling out this feature to production tenants in mid-June; the rollout will be complete by the end of June.
- We will then roll out the feature to the remainder of our tenants in early July; the rollout will be complete by the end of July.
How this will affect your organization
Users will see a notification in Outlook on the web that states that their inbox storage has reached at least 90% of its capacity. This message appears on the bottom of the folder column. It includes a direct link to settings, where the user can address the storage issue by deleting emails.
Should the inbox reach 100% storage, the user will no longer be able to send or receive email messages until they free up storage. To do so, they should click on “storage settings” on the notification or go to Settings > General > Storage and review which folders are taking up the most space and then permanently delete stored files.
What you need to do to prepare
You might consider updating your user documentation and training.