HOW TO: Show number of items per folder in O365 Mailbox

Overview

From time to time it may be necessary to count the items per folder in a Target mailbox. Especially if user migration reached folder quotas errors:

ISSUE: Storage quota exceeded error for mailbox that has not... / cloudficient

This can be achieved using the powershell scrip bellow:

Solution

1. Open Powershell as administrator and Connect to Exchange Online:

Connect-ExchangeOnline

2. Once connected run the following command for the specific user

Get-MailboxFolderStatistics -Identity user@contonso.com | Select Name,FolderSize,ItemsinFolder

This will list all the folders from user mailbox with the size and the item count.