Outlook 2016 slow sending and receiving


I just got my wife a new PC. No complaints otherwise, but I installed a new version of Office, including Outlook (Microsoft Office Professional Plus 2016/Outlook 2016 MSO 64-bit). It is running Windows 10.

She works quite a bit from home and uses Outlook for her work mail. I copied all the email settings from her old Outlook to this new version. She called her work's ISP and they got her all of her old messages and had her set up an .ost file. I've used .pst files before, but never ost (she had a .pst on her old PC). Outlook worked fine on her old PC with an older version of Outlook, but it is incredibly slow with this new version.

I'm a software engineer, so I can usually fix these issues pretty quickly, but this one has me beat. Symptoms:

  • Sending a message takes a minute or more
  • An item sent can take 15 minutes or more for her to receive
  • At the bottom of the Outlook window, a "working" bar appears saying "Synchronizing 'Inbox'" (other folders appear sometimes, like 'Sent items'). It never goes away.
  • A Send/Receive bar at the bottom (next to "working" bar) goes about halfway, and never completes.

I tested the email account settings when setting it up, and they completed fine, but it still took 10 minutes or so to receive the test email.

I know problems like this are hard to diagnose and fix, but I'd appreciate it if someone could at least give me some things to try. To answer the obvious, yes, I did shutdown and reboot (several times).

Best Answer

Outlook is full of settings that are difficult and non-intuitive to locate.

One thing that could cause a message to take longer to send (that is, to leave Outlook) is whether it is already synchronized with the server or no.

Check this setting:

File > Info > Account Settings (button) > Account Settings (menu item)

And find your mail account in the E-mail tab and choose Change (should take you into the Account Settings panel)

Check that Mail to keep offline is set to All:

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Another thing to try is, in the same Account Settings panel, click on More Settings then go to the Advanced and make sure the Purge items when switching folders while online is checked. The reason I suggest this is that (unless I'm wrong) it may perform some cleanup on the local db.

Also, in that same Advanced panel, I have for Server Timeouts set to 1 minute. Maybe that could help?

Here is something I found which has a few more ideas (Bear in mind I have not tried any of these things):

Make sure Outlook is closed. Then locate and run scanpst.exe with your *.pst outlook data file as the parameter. (This is the Inbox Repair Tool)

If that doesn't work, use your Office CD to run a repair.

Finally, try opening Outlook in safe mode by typing this in the RUN box:

Outlook.exe /safe
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