How to Clear the Outlook Cache

Delete all the files in Outlook's RoamCache folder to clear the cache

By
Heinz Tschabitscher
Heinz Tschabitscher
Heinz Tschabitscher
Writer
  • University of Vienna
A former freelance contributor who has reviewed hundreds of email programs and services since 1997.
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Updated on April 11, 2024
Reviewed by
Jon Fisher
Jon Fisher headshot
Reviewed by Jon Fisher
  • Wichita Technical Institute
Jonathan Fisher is a CompTIA certified technologist with more than 6 years' experience writing for publications like TechNorms and Help Desk Geek.
lifewire's editorial guidelines

What to Know

  • If Outlook behaves strangely, the cache might be outdated or corrupted. It's safe to delete the cache to fix these issues.
  • Enter %localappdata%\Microsoft\Outlook\RoamCache into the Run dialog box and delete all the files in that folder.
  • To fix problems with the auto-complete list, go to File > Options > Mail > Empty Auto-Complete List.

This article explains how to delete Microsoft Outlook's cache and how to clear the auto-complete cache. Instructions apply to Outlook for Microsoft 365 and Outlook 2019, 2016, 2013, and 2010.

Delete the Outlook Cache

Microsoft Outlook stores its cache in a specific folder, which you can open and look through if you like. Deleting the cache just means erasing the contents of that folder. Here's how it works:

  1. Save any work and close Outlook.

  2. Press Win + R.

  3. In the Run dialog box, type this and then press Enter to view the cache files: 

    %localappdata%\Microsoft\Outlook\RoamCache

    In the Outlook folder is the OST file used by your email account. According to Microsoft, these are copies of items that are saved on a mail server and are used when you have an Exchange account. It's safe to delete this data file if you're having troubles with your email after having an Exchange account.

  4. To delete the cache files, click somewhere in the folder, press Ctrl + A to select all the files, and press the Delete key (or right-click the selection to find the delete option).

    Outlook cache files selected for deletion in the RoamCache folder

  5. If you're prompted to confirm the deletion, press Yes.

    Your emails and contacts are safe when you clear the cache in Outlook. Deleting the cache really just forces Outlook to pull new information from online instead of from your hard drive. Additional files will be cached again after you erase the existing files.

Clear Auto-Complete Cache

If you only want to clear the auto-complete cache, either turn off auto-complete so the cached data doesn't display or delete the auto-complete cache completely.

  1. Go to the File tab and choose Options.

    The Microsoft Outlook File menu options

  2. In the Outlook Options dialog box, select the Mail tab.

  3. To turn off autocomplete, scroll to the Send messages section and uncheck the box next to Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines.

    Outlook Options open to the Auto-Complete option

    If you want to clear the auto-complete cache without disabling the feature, select Empty Auto-Complete List and then press Yes on the confirmation prompt.

  4. Select OK to save and close.

FAQ
  • How do I delete an address from my autocomplete list in Outlook?

    To delete an address from your Outlook autocomplete list, open a new message, enter the name in the To field, then highlight the name in the autocomplete list and select X. In Outlook Online, go to the View Switcher and select People, choose a contact, select Edit, then delete the address.

  • How do I permanently delete emails in Outlook?

    To delete emails in Outlook permanently, select the message and press Shift+Delete, then select Yes to confirm. To permanently delete Deleted Items folder contents, right-click the folder and select Empty Folder.

  • How do I automatically empty the trash in Outlook?

    To empty the trash in Outlook automatically, go to File > Options > Advanced and check the box next to Empty Deleted Items folders when exiting Outlook.

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