Delay with preparing mailbox for user

Hello LJE24,

Thank you for reaching out regarding the delay in preparing mailboxes for new users in Microsoft 365.

Typically, mailbox provisioning should be completed within 30 minutes, but occasionally it can extend up to 24 hours. The delay you’re experiencing could be due to a few factors, such as licensing issues, service interruptions, system load, or configuration errors.

For guidance on dealing with delays in mailbox provisioning, you can refer to the detailed information available here: Delays in provisioning a user or mailbox - Exchange | Microsoft Learn

Microsoft also recommends the following steps:

1. Verify User Licenses: Double-check that the new users are assigned valid Exchange Online licenses. Reassigning the licenses if necessary may help.
2. Check Service Health: Visit the Microsoft 365 admin center to review the status of services and see if there are any advisories that might be affecting mailbox provisioning.
3. Clear Browser Cache: Clearing your browser’s cache or trying a different browser can sometimes resolve display issues in the admin panel.

If these steps do not fix the delay, contacting Microsoft Support will be the most effective course of action. They will run some advanced synchronization tools to diagnose and address the issue at either the user or organizational level.

Please note that, as forum moderators, we don't have the capability to collect or analyze detailed logs due to privacy and access constraints. Therefore, the best approach is to contact Microsoft Support directly for further assistance.

Here’s how your Office 365 Global Admin can proceed:

• Submit a Service Request: The Global Admin should create a service request with Microsoft Support for further assistance and diagnostics. Detailed instructions can be found here: Get support - Microsoft 365 admin.
• Find Your Microsoft 365 Admin: If you’re unsure who the Global Admin is, guidance on locating them can be found here: How do I find my Microsoft 365 admin?.
• Call Microsoft Support: For additional assistance, the Global Admin can use this link to find the appropriate contact number: Global Customer Service phone numbers - Microsoft Support.
• Contact a Reseller (if applicable): If your Office 365 subscriptions are managed through a reseller, the Global Admin should contact the reseller’s support provider to initiate the service request.

Note: If you’re an end-user, please coordinate with your Office 365 Global Administrator to follow these steps.

Thank you for your patience and understanding.