Fix Outlook if It’s Running Slow in 4 Steps

Check the most comprehensive tips to boost Outlook's performance

Let us explore Outlook and help you fix issues connected to the service running slow.

Outlook has performance issues caused by a corrupt or damaged PST file, an add-in that isn’t functioning, a corrupt profile, or a problem with the Outlook application.

This article presents all you need to know to resolve these issues.

How does Windows registry get corrupted?

When Outlook 365 is running slow, it could be the installed add-ins to blame. To verify, run Outlook in Safe Mode, and if the performance improves, remove the non-critical add-ins.

Also, Outlook could be slow when recent updates and patches are not installed. Running an outdated version of any app can cause issues with both performance and security.

Besides, a corrupt or damaged Outlook profile, and third-party conflicts, usually from installed antivirus, can be behind Outlook 2016 running slow.

Why are my emails slow coming through?

There are a few reasons you may encounter delays in receiving your emails. On top of the list are the following:

  • The email size or size of its attachments
  • Your network latency
  • Issues with backing up virus/spam scanners
  • Delays between recipient or sender client

In most cases, you may not be able to do much about the delays; for example, the sender and recipient client may have a fixed interaction period spanning a few seconds to some minutes.

You may have to wait it out.

How long does it take for Outlook to send emails?

When Outlook is online and linked to a network, emails will be sent immediately after you click Send. Likewise, emails will be sent when the following Outlook is online if you send them when the service is offline.

The solutions below will work for the following error variations:

  • Outlook slow to open/send/receive emails – Adjust the send and receive settings as we have shown in the first solution.
  • Outlook slow and not responding – Delete RSS feed in order to improve the performance of Outlook.
  • Outlook slow to load emails – You might need to delete old emails, as the storage is getting crowded.
  • Outlook slow to sync with Gmail – Disable add-ins in order to make Outlook perform better.
  • Outlook slow and crashing – Compact your files in order to free up more space for future emails.
  • Outlook slow synchronizing – Log out then log in back into your account in order to restart the synchronization process.

How do I fix a slow Outlook on Windows 10?

Before jumping into any complex solutions, we encourage you to check the network connection and verify that you are receiving a decent speed. Slow Internet speed is a common underlying cause of Outlook issues.

Also, if you would rather skip fixing Outlook, you may try other options. For example, we recommend looking into the best Windows 10 email client apps because they provide plenty of valuable features.

1. Adjust send and receive settings

  1. Click on File.
  2. Select Options from the lower left corner.
  3. Click Advanced and scroll down to Send and Receive section, then select Send/Receive…
  4. Under Setting for group, adjust the time to a reduced value.

2. Disable RSS feeds

  1. Click on File.
  2. Select Options from the lower left corner.
  3. Click Advanced and unselect the two options under RSS feeds.

3. Disable add-ins

  • Click on File.
  • Select Options from the lower left corner.
  • Click Add-ins and select COM add-ins, then click the GO button.
  • Find the suspect add-ins and uncheck their corresponding boxes.

4. Compact data files

  • Click on File.
  • Expand the Account Settings option and select Account Settings.
  • Click on Data Files, select any of your data files, and click on the Settings option.
  • Click the Compact Now button.

That’s it! By now, you should have Outlook running again, and it wouldn’t be slow anymore. However, for more official solutions, check out what Microsoft’s support page for Outlook performance issues.

The fixes above would come in handy if Outlook is having slow synchronizing, is slow to open emails, receive emails, send emails, or load emails. You will also find them convenient if Outlook is slow and not responding.

Were you able to fix Outlook running slow in Windows 10 using the solutions above? Let us know in the comments section below.

— Update: 19-03-2023 — found an additional article Outlook 365 Slow Loading: 5 Amazing Tips and Tricks from the website for the keyword outlook is very slow to load.

Microsoft Outlook is one of the most popular and widely used pieces of email management software. It is an integral part of the Microsoft Office 365 suite and makes handling emails a breeze for users. Apart from allowing users to send and receive emails, Microsoft Outlook also enables them to manage their calendars and appointments, take notes, manage their contacts and tasks, and so on.

Because of its unique features, user-friendly interface, and ease of usage, millions of individuals, small and big businesses alike, and everyone else in between now use Microsoft Outlook. However, just like every other application out there, Microsoft Outlook is not perfect. It comes with its own set of issues and glitches.

Slow loading is one of the major issues that users face with Outlook. Sometimes, the application becomes sluggish and takes several minutes to respond, while in other instances, it totally freezes up.

If you are dealing with the problem of slow loading with Outlook, this article is for you. Today, we will talk about what causes this problem, and how you can solve it in just a few minutes. Let’s get started.

What Causes Outlook 365 Slow Loading?

Dealing with the slow loading of Outlook can be annoying. It becomes even more frustrating when you have to respond to an urgent email or adjust your calendar for a last-minute change. This not only degrades the user experience, but also results in a loss of both time and productivity.

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There are several reasons Outlook might be slow to load or start. Let’s have a quick look at a few major ones.

Your computer is performing background tasks

When your computer starts various tasks in the background, like running antivirus scans or starting up multiple programs, it can cause Outlook to perform slowly. So, if you start Outlook when your computer performs several background tasks, it will take too long to load.

Your message folder has reached its full capacity

Another reason Outlook 365 may take too much time to load is that your message folder has reached its capacity. Microsoft Outlook stores all the emails (including the ones you have deleted) in a single file with a PST extension.

When this PST file reaches its maximum capacity, it can degrade the performance of Outlook, making the whole experience sluggish.

Outlook has too many add-ins

By default, Outlook comes with many add-ins that enable it to integrate easily with social media, messaging apps, and other applications. These add-ins are additional resources that Outlook needs to load together with your emails and other information. So naturally, it increases its loading time and negatively bogs down its performance.

Your computer does not have enough resources/memory

Generally, you need to have more than 500 MB of memory to run Outlook on your PC. This is almost double what is required to run Excel or Word. So, if you do not have enough computer resources on a computer which has several large applications, it will ultimately lead to poor performance in Outlook.

Outlook is sharing multiple calendars

Microsoft Outlook is not just your typical email app; it is much more! Outlook offers you several features and functionalities that make managing your work simpler.


And perhaps, one of its best features is that Outlook allows you to manage and share your calendar. However, a shared calendar also means additional data that Outlook will need to load. So, sharing multiple calendars can often lead to slow loading.

5 Super Effective Tips to Solve the Problem of Slow Loading in Outlook 365

Now that we understand what causes the problem of slow loading within Outlook, it’s time to find a solution. But don’t worry, as troubleshooting the slow loading problem is not as difficult as it may sound. In fact, with the right trick, you can get it done within a few minutes!

Search for problem-causing add-ins and disable them

As we explained earlier, add-ins can often lead to the problem of Outlook 365 slow loading. You can open Outlook in Safe Mode. If it works fine in Safe Mode, it means that add-ins are causing problems. Luckily, we can resolve it as well!

Outlook 2016 and newer versions allow you to look for the most problematic add-ins that lead to slow loading and disable them.

Here’s how you can do this.

Step 2: Go to the right pane, scroll down, and click on the ‘Manage COM Add-ins’ option.

This will let you see all the add-ins causing performance issues in Outlook. Now, simply disable those add-ins you don’t need, and you’re good to go.

Disable the RSS Feeds

RSS feeds keep the user up-to-date with the recent updates and changes. But since RSS feeds get updated in real-time, it can affect the performance of Outlook, making it glitchy or slow.

You can disable RSS feeds and see if it improves the performance of Outlook. Here’s how you can do that:

Step 2: You will now see a list of RSS feeds. Uncheck all of them.

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Step 3: Disable the ‘Synchronize RSS Feeds to the Common Feed List’ option.

Step 4: Restart Outlook to see if the problem of slow loading has been resolved or not.

Delete your current Outlook profile and create a new one

The profile settings enable Outlook to load the email accounts of all the logged-in users. However, if you see the message ‘Profile Loading’ while opening Outlook, it might mean that your profile has been corrupted. This leads to slow loading and performance issues.

Follow these steps to solve this problem:

Step 2: Make a copy of your existing Outlook profile for backup.

Step 3: Now delete the current Outlook profile and create a new one.

This will probably make Outlook load faster.

Emails with large attachments and files

Some people often send emails with large attachments or personal files to multiple people. Such large emails bog down the entire network or can even block it. So, your emails will load slowly, or your application might end up freezing.

It is recommended not to send emails with large attachments to several people at once. Instead, try to store those attachments in the cloud and simply share the link with others.

Manage large PST files

Another quick way of fixing the problem of slow loading in Outlook 365 is compacting the size of PST files.

Microsoft Outlook saves all your archived emails as a .pst file. Now, if the file size of these PST files goes out of control, it will cause a problem with Outlook. However, you cannot reduce the size of these files by simply deleting your emails from the inbox.

Here’s how you can compact the size of PST files:

Step 2: Now, go to the Data Files tab.

Step 3: Select the PST file that you want to compact. It usually appears with the name ‘Archives.’


These tips and tricks should help to resolve the problem of slow loading and improve the performance of Outlook.

In addition to the tips mentioned above, always make sure that you are not using older versions of Outlook. For smoother performance, get the latest updates regularly. Also, ensure that you have a proper internet connection and no problems with your network.

Tech Masters has helped countless business owners achieve greater productivity and streamlined workflow with superb IT support. Contact us today to make a difference in your business.


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