Outlook not receiving new email

Copper Contributor

Outlook on Windows 10 is now only synchronizing my Office 365 accounts on startup.

 

We use Office 365 E3 on the monthly update cycle, so the Office apps should be up-to-date. Laptops are all running Windows 10 1709 (16299.371). Many of us have multiple Office 365 accounts set up. I'm guessing this started for me 3 or 4 weeks ago. If I go to Send/Receive and click "Update Folder", it just sits there "Processing" forever. If I close Outlook and start it again, a flood of new email comes in and all the deletes and folder moves I made since the last start are visible in OWA. But it seems nothing happens after that first sync. I do seem to be able to send email, but that's all.

 

Last week, this started happening to a couple of our other users. And more this week. So it's getting to be a bigger issue. I can handle watching my email on OWA, but normal users have no tolerance for "it just doesn't work". 

 

I've tried quite a number of things--even deleting the whole Outlook profile, removing the OST files and configuring again from scratch. That seemed to help for a few days and then it stopped working again. I'm not out of disk space. The laptop is less than a year old with 16GB RAM. 

 

I've inactivated all the add-ins except Microsoft Exchange and Skype Meetings.

 

The fact that it syncs fine on startup is good, but annoying. It means it CAN sync, but just DOESN'T.

 

Does anyone have any ideas how to fix this?

3 Replies

What's the size of the OST file? This looks exactly like some issue with corruption of said file, which is usually caused by excessive size. RAM doesn't really matter here.

After weeks of it not working, I removed another account from the same domain from my Outlook today since it stopped updating this week, and magically, my primary account started working again this afternoon. But to answer the question:

 

From File Explorer: 5.68 GB (6,104,621,056 bytes)

From Outlook: 7059043 KB

5GB is a normal size, that shouldn't be a problem. Another thing you need to be careful about is the number of connections opened, which is dependent on the number of folders in a mailbox, among other things. Thus having mailboxes with dozens upon dozens of folders can also cause connectivity issues. Basically what's detailed here: https://support.microsoft.com/en-us/help/2768656/outlook-performance-issues-when-there-are-too-many-...