How to Clear New or Legacy Outlook Cache on PC or Mac

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Optimize Outlook's performance by clearing the cache

Co-authored by Hannah Dillon Reviewed by Stan Kats

Last Updated: November 30, 2025 Fact Checked

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• New Outlook (Windows)
|
• Classic Outlook (Windows)
|
• New Outlook (Mac)
|
• Legacy Outlook (Mac)
|
• Auto-Complete Cache (Legacy)
|
• Video

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Is your Outlook app not working properly? One way you can try to fix it is by clearing the Outlook cache. A cache is a collection of files that an app uses to run faster, but sometimes these files can become corrupted or stale, causing the app to malfunction. Clearing the cache is an easy and safe way to try and fix an Outlook app that isn't working. In this article, we'll teach you how to clear the cache in both the new and legacy Outlook apps on Windows and Mac.

Clearing the Outlook Cache

• New Outlook for Windows: Press Windows key + R, type "olk.exe --devtools", and press Enter to clear the local cache and cookies.
• Classic Outlook for Windows: Delete the contents of the "%localappdata%\Microsoft\Outlook\RoamCache" folder to clear the cache.
• Outlook for Mac: Go Tools > Accounts… > your account > Reset Account to clear the cache.

Steps

Method 1

Method 1 of 5:

New Outlook (Windows)

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1. 
   1
   Close the Outlook app. You can't clear the Outlook cache if the app is open, so ensure it's fully closed before continuing.

   • You have the new Outlook if the program icon is an envelope with an "O" in the corner. You'll also see Home, View, and Help (but no File button) in the ribbon at the top of the screen.
2. 
   2
   Open the Run dialog. To do this, press ⊞ Win+R.
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3. 
   3
   Type olk.exe --devtools and press ↵ Enter. This will run the olk.exe --devtools command, which is what you need to clear the cache in the new Outlook application.

   • Once you run this application, Outlook will open, as well as the DevTools window.
4. 
   4
   Click Application on the toolbar. It's at the top of the screen. You may just see the tab icon, which looks like a rectangle with a line across the top (like a computer window), or it may say Application.
5. 
   5
   Expand the Local storage tab. It's in the sidebar, under the "Storage" header.
6. 
   6
   Right-click on https://outlook.office.com and select Clear. This will clear your local Outlook cache in the new version of Outlook.
7. 
   7
   Expand the Cookies tab. It's in the sidebar, still under the "Storage" header, and a few lines below the Local storage tab.
8. 
   8
   Right-click https://outlook.office.com and select Clear. This will clear Outlook's cookies, which may contain corrupt or old data. However, clearing the cookies may mean you'll need to log into Outlook again when you open it.

   • Once you're done, you can close Outlook and the DevTools window. You can now reopen Outlook and continue to use it as normal.
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Method 2

Method 2 of 5:

Classic Outlook (Windows)

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1. 
   1
   Close the Outlook app. You can't clear the Outlook cache if the app is open, so ensure it's fully closed before continuing.

   • These steps work for the classic Outlook app, including Outlook 365, 2021, 2019, 2016, and earlier.
   • If your Outlook app has an icon of a piece of paper coming out of an envelope with an "O" in the corner, you have classic Outlook. You also have a File button in the upper-left corner.
2. 
   2
   Open the Run dialog. To do this, press ⊞ Win+R.
3. 
   3
   Open the RoamCache location via Run. To do this, type or paste this path into the Run dialog box and press ↵ Enter: %localappdata%\Microsoft\Outlook\RoamCache.

   • Running this command will immediately open the RoamCache folder in Windows Explorer.
4. 
   4
   Click into the folder and press Ctrl+A. This will select all the files in the folder.
5. 
   5
   Delete all the files. You can do this by right-clicking on the selected files and choosing Delete, or you can press Del or Delete on your keyboard.
6. 
   6
   Close Windows Explorer and open Outlook again. Outlook will rebuild any necessary cache files when it's first opened.
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Method 3

Method 3 of 5:

New Outlook (Mac)

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1. 
   1
   Click Tools > Accounts…. The Tools option is in the bar along the top of the screen, and the Accounts… option is in the drop-down "Tools" menu.

   • Ensure your computer is connected to the mail server before continuing.
   • If you open Outlook and you see that the Legacy Outlook toggle is turned off, you're using the new Outlook app. Note that Legacy Outlook will be retired on October 1, 2026.
2. 
   2
   Click the account you want to clear the cache of. It will be in the left pane.
3. 
   3
   Click the button with three dots. It's in the bottom-left part of the screen. The button has three dots in a circle, and there's a down arrow next to it.
4. 
   4
   Click Reset Account. This will clear out your cache. However, it will also delete any information not synchronized with the mail server, so ensuring you're connected to the server before you reset your account is very important.
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Method 4

Method 4 of 5:

Legacy Outlook (Mac)

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1. 
   1
   Right-click the Exchange folder that you want to clear the cache for. If you can't right-click, you'll need to hold down Ctrl while left-clicking.

   • Make sure you're connected to the Exchange server before continuing.
   • If you open Outlook and you see that the Legacy Outlook toggle is turned on, you're using the Legacy Outlook app. Note that Legacy Outlook will be retired on October 1, 2026.
2. 
   2
   Click Properties. This will open a new window with some settings.
3. 
   3
   Click Empty Cache in the "General" tab. This will clear out the cache for your Exchange folder, and any necessary cache items will be redownloaded by Outlook automatically.
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Method 5

Method 5 of 5:

Clearing the Auto-Complete Cache (Legacy)

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1. 
   1
   Click File > Options. The File button is in the upper-left corner, and the Options button is at the bottom of the side panel.

   • These steps will only work in the Legacy version of Outlook.
2. 
   2
   Click Mail. It's in the left-hand sidebar, and it's the second option from the top.
3. 
   3
   Click Empty Auto-Complete List. It's under the "Send messages" header. You may have to scroll a bit to find this option. The button is on the right-hand side of the window, across from an option that says "Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines."

   • This will clear out your Auto-Complete List, which may hold outdated or incorrect emails. As you continue to send emails, your Auto-Complete List will be rebuilt.
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