Microsoft 365 Business mailboxes now reach 100 GB
Reviewed by Helen Jones
Microsoft says eligible Microsoft 365 Business Basic, Business Standard and Business Premium users now receive an extra 50 GB of primary mailbox capacity, reaching a 100 GB maximum. The increase uses the EXCHANGE_STORAGE_50GB service plan and rolls out through September; it does not add archive-mailbox capacity or stack with another 100 GB Exchange entitlement.
Mailbox complaints often lead admins to buy or assign the wrong Exchange add-on, while a tenant may simply be waiting for the new service plan to provision. A user’s effective quota can also stay below 100 GB when an admin has deliberately set a custom limit. This is a licensing-state check, not a promise that every mailbox becomes 150 GB. The useful distinction is between a Business-suite user with both enabled service plans, a standalone Exchange Plan 1 user that remains at 50 GB, and any mailbox with a custom quota.
Analysis
Sample five Business Basic, Standard or Premium mailboxes in Microsoft Graph and confirm EXCHANGE_STORAGE_50GB is provisioned. Then check Exchange Online PowerShell for the effective quota before changing licences or custom limits.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "Microsoft 365 Business mailboxes now reach 100 GB", Collab365 Spaces.