Outlook Office 365 performance

Copper Contributor

Hello,

In our organization we encounter serious performance issues for users when they are using outlook. some examples the users have reported to us are:

- Wait time of 2-3 minutes after clicking on the search bar before they even have entered a search word(s)
- Slow response time when switching from mailbox to mailbox.
- During use Outlook reports "Trying to connect to server".
- Outlook freezes for a short period while going through one mailbox.

The above are the most reported problems to us.

 

To try and help the users we have tried the steps of the following Microsoft sites:

https://learn.microsoft.com/en-us/outlook/troubleshoot/performance/outlook-performance-is-slow-in-of...

https://learn.microsoft.com/en-us/outlook/troubleshoot/performance/outlook-not-responding-error-or-o...

https://learn.microsoft.com/en-GB/outlook/troubleshoot/performance/performance-issues-if-too-many-it...

We are wondering if any of you can help us improve the performance of Outlook.

 

Some more information:

Our user are working in Citrix on Windows Server 2016 with Citrix Director 7.15.3000.

All our mailboxes are Office 365 mailboxes and we use Office (32 bits) Semi Annual channel for updates. We have set the .ost file size set to download the last 6 months.

4 Replies

Hi @Bsteenbergen,

If you already performed all the standard troubleshooting and nothing helps, your issue is probably network related. 

- How is the performance in OWA?

- How is the performance of other office apps?

 

You could try to run a Fiddler trace while reproducing the issue, ( Download Fiddler Web Debugging Tool for Free by Telerik ), and also use the connectiviy analyzer from the Admin Center:

admin.microsoft.com - Health - Network Connectivity 

FcoManigrasso_0-1679326924567.pngFcoManigrasso_1-1679326952406.png

You have also an online test: Microsoft 365 network connectivity test (office.com)

( Run this one form an affected device ).

 

Please ensure that all this is open with your network team:

 

FcoManigrasso_2-1679327069695.png

Source: Office 365 URLs and IP address ranges - Microsoft 365 Enterprise | Microsoft Learn

 

@Bsteenbergen 

Apart from the performance analyzer tool, any idea for the location of Citrix hosting and your Microsoft 365 tenant? 

Hi@FcoManigrasso 

 

so we ran a network connectivity check from the admin portal, you can see the result below.

Bsteenbergen_0-1680075065020.png

 

For Exchange we score 100 points. so you would think that network connectivity isnt the problem.

 

On the topic of other office apps we dont really notice that kind of performance drop as some of our users have with outlook. the only app which can be slow at times is Teams and we now we can improve this and it is on our to do list to look at, all the other Office apps we use work as expected.

 

Outlook in OWA works better, but that can also be because the users then only have 1 mailbox open per tab in their browser.

 

So talking about the amount of mailboxes, in our organization I can see a correlation between users who have multiple mailboxes assigned to them and the performance issues. but we are just not sure if we can pinpoint this problem on the fact that they have multiple mailboxes.

Just to give a impression about this, there are a few departments where users have 20-25 shared mailboxes connected to them in Outlook. Is there a possibility that this amount of shared mailboxes can cause performance issues in Outlook?

Hi @Bsteenbergen,

 

Thanks for sharing the connectivity test. Looks pretty good.

Regarding your question, the answer is absolutely yes.

As per your description, I would bet that if you create a new profile for one of those affected users with only his/her main account, they'll not face the issue.

At this point, I sugest to check how those extra mailboxes are added to the profile, ( additional accounts, shared folders, automapped mailboxes... ), and may check if, regarding those additional mailboxes, there's one in common for all the affected users, ( maybe there's a particular mailbox with a huge size that's causing the performance issues ). 

 

You can try also to compact the Outlook data file:

 

FcoManigrasso_0-1680079198047.png

 

And uncheck "download shared folders" if you have additional mailboxes added there:

 

FcoManigrasso_1-1680079279010.png

 

The number of shared folders and mailboxes that you can have open without issues depends on several factors, including hardware, mailbox size, size of the shared folders or mailboxes, number of folders in a shared mailbox, item count in folders, and network speed. A computer that has slower hardware, a large mailbox, and slow network connection may not be able to open more than five shared folders or mailboxes. However, a faster computer that has a smaller mailbox and a fast network connection may be able to open 10 or more shared folders or mailboxes.

 

Find here more information:

 

Slow performance if many shared folders or mailboxes open - Outlook | Microsoft Learn

 

Outlook performance issues in a Cached Exchange Mode .ost or .pst file - Outlook | Microsoft Learn