Outlook stores data in cache temporarily for quicker access. But with time, this cache builds up, which can cause the software to slow down. It can also cause errors and synchronization problems. 

The best way to fix the problem is to clear the Outlook cache. This guide will show you how to clear the cache in Outlook

It’s a straightforward process which takes a few simple steps. Whether you want to improve Outlook’s performance or are experiencing issues, clearing the cache is a great place to start.

Let’s begin. 

What Is Outlook Cache?

Outlook cache is a temporary storage space that the Outlook program uses to store information.

This includes data that Outlook retrieves from the mail server, such as email messages and attachments.

The cache’s primary function is to speed up access to frequently used data, which improves Outlook’s overall performance.

But, with time, the cache may fill up with a lot of data, leading to performance issues, synchronization problems, or errors. 

Deleting these temporary files enables Outlook to rebuild the cache with current and relevant data. 

Why Does Outlook Use Cache?

The main reason why Outlook uses cache is to give you instant access to your mailbox contents, regardless of whether you’re offline or have a slow internet connection.

The cache also helps users who travel frequently or work in places with poor internet connections to access their mailboxes. 

Furthermore, the Outlook cache minimizes the number of requests delivered to the server, which can also help reduce network traffic. 

With cache, Outlook only needs to synchronize changes made to the local copy of your mailbox with the server instead of downloading your whole mailbox every time you connect to the server.

Types of Data Stored in the Cache

Outlook’s cache holds different types of data to provide quicker access and better performance. Here are some of them:

1. Email messages

You can retrieve email messages and their attachments more quickly from the cache when you open your mailbox.

Also Read: How to Download All Emails from a Server in Outlook?

2. Calendar information

The cache also stores calendar events, appointments, and related information, giving you faster access to your schedule.

3. Contacts

Cached data contains names, email addresses, and other contact information you can quickly access when writing emails or setting up appointments.

Related: How to Insert Outlook Contacts into a Word Document?

4. Attachments

Emails with file attachments are cached to help you open and preview files faster.

5. Offline address book

Outlook keeps a cached copy of the offline address book to access contact details even when you’re not online.

6. Search index

Cached search indexes help make Outlook’s search functionality faster. This makes it easier to search for specific emails or items.

Signs it’s Time to Clear Outlook Cache

There are several signs that show it’s time to clear Outlook cache. Let’s go through them:

1. Slow Outlook performance

When you realize that Outlook is running slower than usual, it may be a sign that a large amount of data has been collected in the cache.

You can resolve the problem by learning how to clear Outlook cache to boost performance and increase response times.

Also Read: How to Fix “MS Outlook Not Responding” Issue

2. Error messages and glitches

Outlook error messages or unexpected malfunctions could be signs of problems with the cached data. 

Clear the Outlook cache to resolve potential conflicts or corruption within the stored information.  

3. High storage usage on devices

Your smartphone’s excessive storage consumption in Outlook may show that the cache has maxed out.

Clearing the Outlook cache can fix performance issues and free up storage space on your device.

Further Reading: How to Get More Storage on PC – Clean Up Your PC to Run Faster

How to Clear Cache in Outlook: Step-By-Step Guide

If you want to know how to clear Outlook cache, follow the steps below.

1. Backup important data

Before you clear Outlook cache, back up your data. This will prevent the loss of crucial information, such as important emails, contacts, or other relevant information. 

Outlook has an export function that you can use to make a backup file. But they may be different depending on the version of Outlook you’re using. 

Here’s how to back up your mailbox on the latest Outlook version released on January 2024: 

  • Open Outlook. 
  • Click the gear icon in the upper-right corner to open the Settings menu.
Outlook settings
  • Type “export mailbox” in the Settings window. 
Outlook Email Accounts
  • Click “Export mailbox” to begin the process. Remember that the process can take up to four days to complete. You’ll receive a link to download it in your mailbox when it’s done. 
Outlook export mailbox

Backing up from previous Outlook versions 

Follow the steps to back up your files for previous versions: 

  • Open Outlook.
  • Click the “File” button at the top left corner.
Outlook Account Information
  • Click “Open & Export.”
  • Select “Import/Export.”
Outlook Import Export
  • Choose “Export to a file” and click “Next.” 
Outlook Export to a file
  • Click “Outlook Data File (.pst)” and select “Next.”
Outlook Data File
  • Choose the folder you want to back up and select “Next.” 
Outlook export file choose folder
  • Select the name and location to store the backup file and click “Finish.”
Export Outlook Data File Finish
Don’t export your .pst file to OneDrive because it’ll block automatic syncing for Outlook .pst files. Also, Outlook will only export the items currently in your cache if you are using Cached Exchange Mode. By default, your cache contains content from the previous 12 months. If you want to export for over 12 months, turn off Cached Exchange Mode before exporting.

2. Locate and clear the cache files

The next step is to search for the cache, which is simple. Remember that this method is for Outlook’s current version.

  • First, press “Windows key + R” to open the Run dialog box. 
  • Then, copy and paste “%localappdata%\Microsoft\Outlook” into the field and press “Enter.”
Run Outlook
  • Search for the “RoamCache” folder to view all the cache files. 
  • Select all files, right-click, and select the “Delete” option. 

How to clear Outlook cache on previous versions

Here’s how to clear cache in Outlook for previous versions: 

  • Open Outlook on your PC.
  • Select “File” in the upper left corner of the Outlook window.
Select “File” in the upper left corner of the Outlook window
  • Click “Options” on the left side of your screen.
Outlook Account Information1
  • Click on “Mail” on the left side of your screen.
Outlook mail
  • Scroll to the “Send messages” section and select “Empty Auto-Complete List.”
“Empty Auto-Complete List
  • A confirmation box will appear. Click “Yes” to clear the Outlook cache.
Empty Auto Complete List Yes confirmation box


Throughout this guide, we’ve discussed how crucial it is to clear the Outlook cache. We’ve discussed why Outlook uses cache, the types of data it stores, and the step-by-step process to back up and clear the cache.

Did you face any challenges clearing your cache? What was your experience? Share your thoughts or questions in the comments below! And don’t forget to rate the article!

Further Reading: How to View and Clear DNS Cache on Windows 10/11?


Yes. You can safely delete the Outlook cache without any issues. The cache holds temporary files that help Outlook to run smoothly. But clearing them won’t affect your data or how the program works. 
How you use Outlook determines how frequently you should empty the Outlook cache. Consider deleting the cache if Outlook starts performing poorly or becomes slow. Some users clear Outlook cache monthly, while others do it every few months.
No. Clearing your cache won’t delete your emails. It only speeds up Outlook by deleting temporary files and data kept for quick access. So, important information and emails are still there.
Yes. You can clear the cache even if you’re sharing the same computer. But remember that doing so may briefly affect the Outlook experience for other users. So, it’s better to let them know first or clear the cache when it’s less disruptive. 
There is no option for Outlook to erase its cache automatically. You’ll need to delete the cache to preserve optimal performance manually. You can tell when to remove the cache by regularly monitoring Outlook’s performance.