Outlook reading pane slow to load for some emails

Question

Some emails that I receive are slow to load in the reading pane, about 30+ seconds, when I click on them in my inbox. It only happens with emails received from internal colleagues, emails from any external email address have no issues.

If I click reply all, I can then also immediately read the email in the draft that opens.

It's been going on for a few months now and my IT support is stumped. I've also tried different options with the automatic download settings but nothing seems to be able to get me back to the way it was originally operating.

I'm using Windows 7 and Microsoft Outlook for Office 365. Thank you.

Answer 1

Some emails that I receive are slow to load in the reading pane, about 30+ seconds, when I click on them in my inbox. It only happens with emails received from internal colleagues, emails from any external email address have no issues.

If I click reply all, I can then also immediately read the email in the draft that opens.

It's been going on for a few months now and my IT support is stumped. I've also tried different options with the automatic download settings but nothing seems to be able to get me back to the way it was originally operating.

I'm using Windows 7 and Microsoft Outlook for Office 365. Thank you.

I have exactly the same problem, but running on Win10. After some experimenting I note that if I start Outlook in safe-mode, everything works fine. But in normal mode, some mails takes forever to open (like several minutes sometimes).

As far as I understand, running Outlook in safe-mode mostly differs in that all add-ins are disabled. But even when I manually disable all add-ins in normal mode, the problem is still there. 

I'm running towards an Exchange server, in cached mode, and the OST file is about 3GB. So not super-large, and again, in safe mode everything works as it should...

Answer 2

We are also experiencing the same problem.  It is only affecting internal co-worker emails.  All outside emails load instantly in the preview reading pane, but any email sent by anyone of our staff takes a long time to load in the preview reading pane.  This issue just literally started happening as of last week.

How to fix?

Answer 3

For anybody else still having this issue. If turning off the outlook add-ons and loading photographs checkbox doesn't resolve your issue, check to see if you are blocking any network connections to Akamai or Microsoft IP ranges.

We were blocking certain IP ranges (owned by Akamai and according to Geo-IP, were located in a different country) and once we allowed them, the problem went away.

Answer 4

We are having the same issue with internal co-worker emails.  I've tried everything, safe mode does not resolve the issue for us.

Curious with other users having this problem, are any of you using a signature manager?

Answer 5

Hello RusselHeller,

Thanks for posting here.

I noticed your system is windows 7,  and the system requirement for Microsoft 365 and office are Windows 10, Windows 8.1, Windows Server 2019, Windows Server 2016(more details about system requirement, please check here), so please try to update your system to check if it will be better.

If issue persist, there are many reasons for outlook performance issue, many of these reasons can be automatically checked by the Microsoft Support and Recovery Assistant (SaRA). To start the automated checks, follow these steps:

1.    Install the Outlook Advanced Diagnostics tool.

2.    Click Run when you are prompted by your browser.

3.    In the report that’s generated, review the items on the Issues found tab. For configuration details about Outlook, Windows, and your computer, review the settings on the Detailed View tab.

More details please check Outlook performance is slow in the Office 365 environment 

In addition, I would like to know are there too many items or folders in a cached mode .ost or .pst file, it will also cause performance issue.

Please feel free to let me know how is it going, we will always be here to help you😊

Best regards,

Regina