Clear Your Outlook Cache: Windows and Mac Guide

Understanding Outlook Cache and Why It Matters

Microsoft Outlook stores temporary files and data on your computer to help the application run faster. These files are called cache, and they include things like downloaded email messages, contact information, calendar events, and website data that Outlook uses regularly. Think of cache like a notebook where Outlook writes down information it uses frequently so it doesn't have to look it up every single time.

Over time, your Outlook cache can become very large. A typical Outlook user might accumulate hundreds of megabytes or even gigabytes of cached data over months or years of use. This buildup can slow down your computer, cause Outlook to freeze or crash, or create problems when syncing your email across devices. Some users report that clearing cache fixes issues where emails won't send or receive properly, or where Outlook takes a very long time to open.

Cache problems are particularly common if you use Outlook with multiple email accounts, receive large attachments regularly, or have been using the same Outlook profile for several years without clearing cache. Windows computers and Mac computers store cache in different locations, which is why the process differs between the two systems.

Understanding what cache does helps you know when clearing it makes sense. You might notice Outlook running slowly, or you might want to clear cache as routine maintenance. Clearing cache won't delete your actual emails, contacts, or calendar items—it only removes the temporary copies that Outlook created to speed up performance.

Practical takeaway: Cache buildup is normal and happens to everyone who uses Outlook regularly. If your Outlook feels sluggish or you're experiencing sync problems, clearing cache is a reasonable troubleshooting step that takes about 15 to 30 minutes.

How to Clear Outlook Cache on Windows Computers

Clearing Outlook cache on Windows involves finding and deleting specific folders where Outlook stores temporary files. The process is straightforward, though the exact location of these folders depends on which version of Windows you're running and whether you use Outlook as a desktop application or Outlook on the web.

For Outlook 2016, 2019, or Microsoft 365 on Windows, the main cache folder is usually located in your user profile under AppData. You'll need to show hidden files first, since Windows hides the AppData folder by default. Open File Explorer, click on the View tab, and check the box that says "Hidden items." Then navigate to C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook. Inside this folder, look for files with names like "*.ost" (offline storage table files) or "*.dat" files. These are cache files you can safely delete.

Another important cache location on Windows is the Temporary Internet Files folder used by Outlook. Navigate to C:\Users\[YourUsername]\AppData\Local\Microsoft\Windows\INetCache. Delete the contents of this folder to clear web-related cache that Outlook may have stored.

Before deleting any cache files, make sure Outlook is completely closed. If Outlook is running in the background, you won't be able to delete these files. Check your system tray to confirm Outlook isn't minimized there. After closing Outlook, you can safely delete the cache files. You don't need to restart your computer, but you can if you want to. When you reopen Outlook, it will recreate the cache files as needed.

If you're using Outlook through a browser (Outlook on the web), clearing cache is different. Use your browser's settings to clear cache, cookies, and temporary files. In most browsers, this is found under Settings or Preferences, then Privacy or History.

Practical takeaway: On Windows, close Outlook completely, navigate to AppData\Local\Microsoft\Outlook and AppData\Local\Microsoft\Windows\INetCache, and delete the files inside. This process takes about 10 minutes and requires no special tools or software.

How to Clear Outlook Cache on Mac Computers

Mac users follow a similar process to Windows users, but the folder locations are different because Mac uses a different file system. On a Mac, Outlook cache is typically stored in your Library folder, which is usually hidden from view in Finder.

To access the Library folder on a Mac, open Finder and click "Go" in the menu bar at the top. Hold down the Option key on your keyboard while you click "Go"—this will reveal a "Library" option that doesn't normally appear. Click on Library, then navigate to Caches. Inside the Caches folder, look for a folder named "Microsoft" or one that contains Outlook-related files. The folder might be named something like "com.microsoft.Outlook" or similar.

You can delete the contents of Microsoft-related cache folders. Before doing this, make sure Outlook is completely closed. You can check by opening Activity Monitor (search for it using Spotlight search) and looking for any Outlook processes running. If you see Outlook running, quit it before proceeding.

Another location to check on Mac is Library\Preferences. Some Outlook preference files can be deleted here as well, though be careful to only delete Outlook-related files. Look for files with names starting with "com.microsoft.Outlook."

On Mac, you should also clear your browser cache if you use Outlook on the web. Open your browser, go to Settings or Preferences, find the Privacy or History section, and clear cached data and cookies.

After clearing cache files on Mac, you can reopen Outlook. Your emails, contacts, and calendar information will remain intact. Outlook will take a few moments to rebuild its cache when you first open it after clearing.

Practical takeaway: On Mac, use Finder's "Go" menu while holding Option to access the Library folder, then navigate to Caches and delete Microsoft or Outlook-related folders. Always close Outlook first to avoid file access problems.

Step-by-Step Instructions for Different Outlook Versions

Outlook comes in several versions, and cache locations can vary slightly between them. Knowing your Outlook version helps you find the correct cache folders. To find your Outlook version, open Outlook, click on "File" in the menu (on Windows) or "Outlook" in the menu (on Mac), then look for "Office Account" or "About Outlook." This will show you the version number.

For Outlook 2013 on Windows, cache files are stored in C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook. The process is the same as for newer versions: close Outlook, navigate to this folder, and delete cache files.

For Outlook 2016, 2019, and Microsoft 365 versions, the folder locations are the same. These newer versions use the AppData\Local\Microsoft\Outlook directory for offline storage files and AppData\Local\Microsoft\Windows\INetCache for internet-related cache.

For Outlook on Mac 2016 and later versions, use the Library\Caches method described in the previous section. Mac versions of Outlook have been relatively consistent in where they store cache files.

For Outlook Web Access (OWA) or Outlook on the web, cache clearing happens through your browser, not through Outlook itself. Each browser has different steps for clearing cache. In Chrome, go to Settings, then Privacy and Security, then Clear Browsing Data. In Safari, go to Safari menu, then Clear History. In Firefox, go to Edit or Firefox menu, then Preferences or Settings, then Privacy.

If you're unsure which version you have, or if you can't find the cache folders in the locations described, you can also use Windows Disk Cleanup (on Windows) or Optimize Storage (on Mac) to clear temporary files. These tools are built into the operating system and can clean up Outlook cache along with other temporary files.

Practical takeaway: Identify your Outlook version first by checking File or Outlook menu, then follow the specific instructions for that version. If you're using Outlook on the web, clear cache through your browser instead of looking for local files.

What to Expect After Clearing Cache and Common Issues

After clearing Outlook cache, you might notice some immediate changes. Outlook may take slightly longer to open the first time, since it needs to rebuild its cache. This usually takes less than a minute. Your emails, contacts