Lastly, be sure to empty the Trash folder frequently enough to avoid a constantly growing Trash folder. Also, you can simply archive messages in outlook to clean them out of your mailbox (be careful as this WILL remove the messages from the server). The recommended method of avoiding this outlook issue is to simply file away messages from these subscribed folders into archived / unsubscribed folders (this also keeps you email organized!). This issue can still be noticed if you have a very large Inbox folder, Sent folder, Trash folder, or any subscribed folder. This will resolve extremely slow synchronizations with Microsoft Outlook platforms.

Click “OK” to close the window and commit the options.

Uncheck the option “When displaying hierarchy in Outlook, show only subscribed folders.” at the bottom of the window.

Do this for any other folders you wish to sync with the server. Knowledgebase Click on Send/Receive > Send Receive Groups > Define Send/Receive Groups.

Select “Templates” and click subscribe.

Select the “All”tab as we are now going to sync folders we wish or need to sync.

I am not sure why it will not keep these settings. Incidentally, I have to do this step over and over. Reduced the subscribed folder list so that the synchronizing is only for Inbox, Deleted, Drafts, Bulk, Sent, etc. This has worked on occasions before, although the issue will occur again. Reduced the number of emails in my Inbox. Fixes I have tried so far are: Deleting the Outlook profile. I have also tried doing Send / Receive - Update Folder but this gets stuck on Synchronizing Hierarchy and does nothing.

It may prompt about folders that cannot be unsubscribed, just click “OK” here. In Outlook itself, the status is Updating Inbox but its not doing anything - its hanging.

Hold shift and click the last item in the list.

Select the first item in the list and scroll all the way down.

Select all items in the list as follow:.

Click on the “Subscribed” tab and click the “Query” button.

After setting up your IMAP email account in outlook, right click on your email account and select “IMAP Folders…”.

This issue is because Microsoft Outlook downloads all messages every time including attachments versus a normal email IMAP application where only headers are synced to present crucial information only, and messages and attachments are ONLY downloaded and cached upon viewing the message or if the mail application is explicitly told to download all messages. Having many folders with many messages in Microsoft Outlook, especially if they have attachments, can be slow.

Outlook stuck on synchronizing inbox