How to make Microsoft Outlook run faster (versions 2019 / 365/ 2016)?


Here’s a question we got from a reader:

Long time lurker, first time asking: Started to use Outlook 365 a couple months ago. Last week i started to notice some lagging in Outlook performance, which became quite slow to refresh my email (send / receive takes longer than usual, inbox syncronization is also somewhat slower). I am wondering why Outlook is so slow, and how should i fix this slowness, before it starts to impact my productivity?

First off let’s try to pinpoint the key reasons for a slow Microsoft Outlook opening and general performance:

  1. Software Add-ins (either from Microsoft or 3rd Parties)
  2. Overall Computer Specs
  3. Networking performance

Let’s break these down.

Speeding up Microsoft Outlook when it runs slow

In this quick tutorial we’ll learn how to troubleshoot performance issues. Not all tips might be fully relevant for your specific situation, but for sure some of them might be helpful.

Fixing slow startup Issues

Disable 3rd party Outlook add-ins

In many cases, the culprit of Outlook performance problems are issues related to 3rd party ad-ins that extend the Microsoft Office capabilities and are installed on top of it.



If you notice that Outlook is somewhat slow on startup, the first thing you should probably do is disable those COM Add-Ins.

Here’s how to do that:

  1. Open Microsoft Outlook
  2. Hit File, then choose Options
  3. The Outlook options will open up, now go ahead and hit the Add-Ins link.
  4. Navigate to the Manage combo box at the bottom of the screen. Ensure COM Add-Ins is selected and hit Go.
  5. You’ll now see a list of all the Add-Ins installed on your Computer.
  6. Uncheck the check box next of each of the items that are not related to Microsoft (for example: Add-Ins releated to your PDF Viewer, Video/Pic Editing, 3rd party communication tools).

Speed_up_Outlook_Com_AddIns

  1. Hit OK.
  2. Now go ahead and restart your Outlook installation.
  3. Check whether your startup time has been shortened. Most cases, this should be helpful.If not, proceed to the next section.

Note: There might be instances in which Outlook will be stuck and won’t open at all. In that case, you might need to startup Outlook in the so called “Safe mode”, just in order to access your Add-Ins list.

Disable Microsoft Add-Ins

If Startup is still slow, you might need to look into Microsoft Add-Ins installed in Outlook (Skype, Teams, Social Connector, SharePoint Server, the Microsoft VBA for Outlook Add-In etc’).



In principle you should execute a similar procedure that was explained before. The only difference would be that in step 6 you should ensure all boxes next to the Add-Ins entries are unchecked.

Speeding up Overall Performance

There are instances in which Outlook startup is fast, however the Send-Receive performance is perceived as slow. If that’s your case, you might need to look into two key topics: your network and your PC.

Always work with local PST files

Outlook data files (*.PST) allow us to archive Outlook mails,calendar, contacts and task items instead of maintaining them on the Mail provider service (be it Exchange or just IMAP). This allows for simler and faster access to those items and obviously reduce your the space quota footprint of your email account. If you keep your PST files on a network drive, you might be invariably experience some slowness when accessing them, especially over WIFI. One thing to always keep in mind is to ensure that the PST files are kept on your Computer.  You should however ensure proper backup of your PST files to a network drive / online storage or portable disk.

Consider an Hardware upgrade

If you perceive some performance degradation when working with large attachments (huge PowerPoints, Excel Spreadsheets etc’), you might need to consider to look into your computer specs. From experience, a minimum of 8GB RAM is typically required for business usage of Microsoft Office, specially if you run several applications in parallel.

Have you experienced sluggish Outlook performance? Feel free to share your experience.

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