How to migrate mailbox with over 500 GB - Migration from GWS to M365

Brass Contributor


I am trying to migrate GWS mailboxes with over 500 GB to M365 utilizing third-party tool.

I have around 50 mailboxes over 200 GB and 10 mailboxes over 500 GB.

With third-party tool, I can migrate Gmail to archive mailbox of M365.

and I am aware of the fact that it needs auto-expanding feature of archive mailbox.

So I have enabled auto-expanding feature for those archive mailbox.


However, the thing is the daily growth rate and 

It cannot exceed 1GB/day as I noticed through below link.

The link says like this.

Auto-expanding archiving is supported only for mailboxes used by individual users or for shared mailboxes with a growth rate that doesn't exceed 1 GB per day.


Is there any way to speed up the growth rate?



And provisioning speed also matters. 

the link goes like under.

After you turn on auto-expanding archiving, an archive mailbox is converted to an auto-expanding archive when the archive mailbox (including the Recoverable Items folder) reaches 90 GB. It can take up to 30 days for the additional storage space to be provisioned.


Is there any way to shorten the days for the additional storage space to be provisioned?


How can I overcome this circumstances?

or is there an other method to do this?


Thank you in advance.

2 Replies



Please try to contact Microsoft support to release on request base

Thank you for the guide.