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One of the users in our on-prem Exchange has thousands of emails in the Outbox on the server but none in the local Outbox when checking the size of the email folders. When clicking the Outbox in the email view it says that it's empty. They take up a lot of space so we need to be able to see them to delete them.
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Hi @KF ，
I wonder how do you check if there are messages in the Outbox on the server?
Are you using the Outlook client that logs on in cached mode? Please refer to the following steps to see if outbox of mailbox is synchronized after using online mode:
Thank you, when unchecking Cached Mode all the e-mails became visible in the outbox.
Hi KF-2744,
There could be many reasons which lead to the synchronization issue.
i) Chances of low disc space can interrupt the smooth synchronization between local OST and exchange server.
ii) Synchronization issues between local offline file & Online mode.
Turn off the cache exchange mode by following the steps shared by @Aholic Liang-MSFT and re-check it. Also, you can delete the OST file and rebuild it again.