How do I fix my outlook storage issue?

Hi Divya,

Thank you for posting your question in the Microsoft Q&A forum. 

Based on your description and the storage banner you shared, it looks like your primary Exchange Online mailbox is approaching the 99–100 GB limit. Per Microsoft’s service description, the storage limits are documented here: https://dori-uw-1.kuma-moon.com/en-us/office365/servicedescriptions/exchange-online-service-description/exchange-online-limits#storage-limits

From that table, a 100 GB primary mailbox typically indicates you’re on an Enterprise plan (E3/E5 or Exchange Online Plan 2). In this scenario:

• If you enable Auto‑Expanding Archiving, your Online Archive mailbox can grow dynamically up to 1.5 TB, giving you significant headroom.
• If Auto‑Expanding Archiving is not enabled, the default Online Archive quota starts at 100 GB.
• Importantly, the Online Archive mailbox uses a separate quota from your primary mailbox, so moving items into the Online Archive reduces the pressure on your primary mailbox limit.

Follow the steps here to enable an archive mailbox for the user: https://dori-uw-1.kuma-moon.com/en-us/purview/enable-archive-mailboxes

After the archive mailbox is enabled, you can turn on Auto‑Expanding Archiving using the guidance here: https://dori-uw-1.kuma-moon.com/en-us/purview/enable-autoexpanding-archiving

Note: Enabling archive and auto‑expanding archiving requires administrator privileges in Microsoft 365. If you’re not an admin, please contact your IT administrator to enable the archive mailbox (and auto‑expanding archiving) on your behalf.

Preview: Auto‑Archiving (different from Auto‑Expanding): Microsoft has introduced a new Auto‑Archiving capability that automatically moves older items from the primary mailbox to the Online Archive when the mailbox approaches its quota. You can read more here: https://dori-uw-1.kuma-moon.com/en-us/exchange/security-and-compliance/messaging-records-management/auto-archiving

For end‑user tips to reduce mailbox size and manage storage from Outlook/Outlook on the web, see: https://support.microsoft.com/en-us/office/mailbox-storage-limits-in-outlook-f170fe90-b859-4034-bcda-e186fc6a26f5

I hope this helps clarify how archiving affects storage and the steps to enable the right features.

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