Migrate Mailbox

Hi there,

Yes, you're right to consider the mailbox size limits, especially with the 150MB restriction set on your Exchange on-premises database.

Regarding the Audit folder in the recoverable items, it's part of the compliance features in Office 365 and typically cannot be deleted manually unless audit logging is disabled. You may want to review whether audit logging is required for this user and, if not, consider disabling it temporarily to allow the Audit folder size to reduce. Keep in mind that even after disabling, it might take some time for the data to clear.

As for the migration, I'd recommend checking out the EdbMails Office 365 Migration. It supports direct migration from Office 365 (cloud) to on-premises Exchange servers, and it handles mailbox mapping, filtering, and data integrity very efficiently—even with mailbox size constraints.

It also lets you exclude certain folders or limit the data range, which can be very useful in your case if you want to skip unnecessary data during the migration process to stay within the size limits.

Hope that helps! Let me know if you need more details on using EdbMails for this scenario.

Visit : EdbMails Office 365 Migration