Clear Cache on the Outlook App: Safe Steps by Device

To clear the Outlook app’s cache, use the method for your device: on Android, open Settings > Apps > Outlook > Storage & cache > Clear cache; on a new Outlook app for Windows, use Windows Settings > Apps > Installed apps > Outlook > Advanced options > Repair or Reset. On iPhone and Mac, the available options differ, and clearing app data or reinstalling can remove local information, so check that unsent messages and other important items are saved first.

What Outlook’s cache contains

A cache is temporary information an app keeps so it can load content or work more smoothly. Outlook may store recently viewed message content, attachments, images, and other account data on your device. The exact files and controls depend on whether you use new Outlook, classic Outlook, Outlook for Mac, or the mobile app.

Clearing a cache is not the same as deleting your mailbox. Messages and calendar entries held by Microsoft 365, Exchange, Outlook.com, or another mail provider normally remain on the server and can sync back after Outlook reconnects. However, not everything visible in an app is necessarily synced. A draft waiting to send, a message in an Outbox, or information kept only on the device could be lost when app data is reset or the app is removed. Check those items before taking a more thorough reset step.

It is also useful to distinguish cache from saved sign-in details, account settings, and downloaded offline data. A cache clear may make Outlook download content again; a reset or reinstall can require you to sign in and set preferences again.

Clear cache in new Outlook for Windows

The new Outlook for Windows is a separate app from classic Outlook. If it is slow, displays stale content, or behaves unexpectedly, try repairing it before resetting it. Repair is intended to fix the app without the broader impact of resetting its stored data.

Close Outlook.
Open Windows Settings, then choose Apps > Installed apps.
Find Outlook in the list, select the three-dot menu beside it, and choose Advanced options. On Windows 10, the route is Settings > Apps > Apps & features, then select Outlook and open Advanced options if that option appears.
Select Repair and reopen Outlook to see whether the issue is fixed.
If repair does not help, return to Advanced options and select Reset. Read the confirmation prompt before proceeding.

Reset can remove locally stored app data and may require you to add or sign in to your account again. Mail that is safely stored on the provider’s server should sync back, but do not assume an unsent or locally saved item will. If Outlook has more than one account, confirm you know the sign-in details for each one. App labels and available options can vary slightly with Windows updates.

Clear cache in classic Outlook for Windows

Classic Outlook for Windows does not have one general Clear cache button. It stores different kinds of local data for different purposes, so deleting a random Outlook folder is not a good first step. If the problem is only an incorrect suggested recipient, for example, clearing the autocomplete list is more targeted than removing mailbox data.

Classic Outlook keeps autocomplete cache files in a RoamCache folder under the user’s local Outlook data. A cautious way to refresh those suggestions is to close Outlook, open File Explorer, enter %localappdata%\Microsoft\Outlook\RoamCache in the address bar, and move the relevant autocomplete cache file to a backup folder rather than permanently deleting it. The file name commonly begins with Stream_Autocomplete, but do not remove other files unless you know what they contain. Reopen Outlook afterward. This affects suggested names, not the messages in your mailbox.

Outlook also uses an offline Outlook Data File, or OST, for some account types. It can be rebuilt in certain situations, but removing it forces Outlook to download mailbox data again and may be risky if the file contains information that exists only locally. Do not delete an OST as a routine cache-cleaning step. If a sync problem persists, first check Outlook’s connection and sync status, install available Office updates, and use Microsoft’s account-specific repair guidance or your organization’s support team.

Clear cache on an iPhone or iPad

iOS does not provide a system-wide Clear cache button for Outlook. First try refreshing the account inside Outlook: open the app, tap the profile icon, tap the gear for Settings, select the affected email account, and look for Reset Account. If the option is available, use it and allow the account to sync again. Menu wording can vary by app version and account type.

If resetting the account does not solve the problem, updating Outlook and restarting the device are lower-impact steps. Reinstalling Outlook is a more complete app reset: remove the app, install it again from the App Store, and sign back in. Server-synced mail should return after synchronization, but verify that any unsent drafts or other device-only information is safe before uninstalling. Reinstalling also does not repair a problem caused by the mail provider, a network restriction, or an account policy.

Clear cache on Android

Android generally lets you remove an app’s temporary cache without clearing its full storage. The exact labels vary by manufacturer and Android version, but the usual route is:

Open the phone’s Settings app and choose Apps or Apps & notifications.
Select Outlook. If it is not listed immediately, choose See all apps.
Tap Storage & cache or Storage.
Choose Clear cache, then open Outlook and give it time to reload.

Choose Clear cache, not Clear storage, Clear data, or a similarly named option, unless you deliberately want a broader reset. Clearing storage or data can remove local app settings and sign-in state. After a cache clear, Outlook may briefly use more data or take longer to display messages while it downloads content again. If a problem remains, try Outlook’s in-app Reset Account option, where available, before clearing all app data.

Outlook for Mac and Outlook on the web

On Mac, the steps depend on whether you are using legacy Outlook or the newer Outlook for Mac. In legacy Outlook, some folders offer a targeted Empty Cache command: Control-click or right-click the folder in the folder list, choose Properties, and select Empty Cache if that command is available. This refreshes the selected folder’s local copy; Outlook may need to download its contents again. Do not empty a folder cache if you have unsynced local items in it.

The newer Outlook for Mac does not necessarily expose the same folder command, and there is no single cache-clearing path that applies to every Mac version. Start by restarting and updating Outlook. If an account-specific reset or repair option appears in Outlook’s settings, use it carefully; removing and adding an account can trigger a fresh sync but may discard unsynced local information. For a managed work account, check with your administrator before removing it.

Outlook on the web is different: it runs in a browser rather than as the Outlook desktop or mobile app. If it shows stale content, reload the page, try a private browsing window, or clear site data for the Outlook website in your browser. Clearing all browser data can sign you out of other sites, so use a site-specific option when possible. Browser cache steps are not the same as clearing the cache of an installed Outlook app.

When clearing cache helps—and when it does not

A cache refresh is most useful when Outlook displays outdated content, repeatedly fails to load a view, or appears to have a damaged local copy. It can also help after an app update if the app’s temporary data is causing a problem. It is not a guaranteed fix for every slow or broken mailbox.

Before resetting anything, identify the symptom and try a smaller fix. If Outlook works on the web but not on your phone, the issue is more likely to be with the app or device than with the mailbox itself. If it fails across devices, check the service status, account access, and internet connection instead. For a message stuck in the Outbox, confirm the device is online and inspect the message size or attachment; deleting a cache is not a substitute for resolving a send error.

Stale messages: refresh or sync the account, then consider an account reset if the display remains out of date.
App crashes: restart and update Outlook; on Windows, try Repair before Reset.
One incorrect contact suggestion: remove or refresh autocomplete suggestions rather than clearing mailbox files.
Account-wide sign-in or delivery trouble: check credentials, provider status, and any work or school account restrictions.

What to check before a reset

“Clear cache” can mean anything from deleting a temporary Android file to resetting an entire Windows app. Before choosing the broadest option, protect anything that might not be on the server and make sure you can get back into the account.

Check Drafts and Outbox for messages that have not been sent, especially if they contain long text or attachments.
Confirm your password and any required multi-factor authentication method are available. A reset may ask you to sign in again.
For a work or school account, consider whether your organization manages Outlook settings or restricts account removal.
Use Repair or an in-app account reset before clearing all app data or reinstalling, when those options exist.
Afterward, keep Outlook open on a reliable connection until folders and attachments have had time to sync.

There is usually no need to clear Outlook’s cache on a schedule. Repeatedly deleting temporary data can create extra downloads and slow the first sync without preventing future problems. Use a targeted reset when there is a specific symptom, and avoid deleting folders or data files manually unless official instructions for your exact Outlook version say to do so.

Frequently Asked Questions

Will clearing the Outlook cache delete my emails?
Usually, messages synced to your email provider remain on the server and return after Outlook reconnects. A full app reset or reinstall can still remove unsynced local items, so check Drafts and Outbox first.

Is Clear cache the same as Clear data on Android?
No. Clear cache removes temporary files. Clear data or Clear storage is broader and can erase app settings and sign-in state. Choose Clear cache for a routine cache refresh.

How do I clear the Outlook cache without reinstalling?
On Android, use the system’s Clear cache option. On new Outlook for Windows, try Repair and then Reset in Advanced options. On iPhone, use Outlook’s Reset Account option if available. The exact choice depends on your device and app version.

Why is there no Clear cache button in Outlook?
Outlook uses different storage systems across Windows, Mac, iOS, and Android. Some versions offer a targeted account or folder reset, while others rely on the operating system’s app settings or a reinstall for a deeper reset.

Does clearing the cache free up a lot of storage?
It may remove temporary files, but the amount varies with how you use Outlook and how long it has stored local content. A reset can also make Outlook download messages and attachments again, so it may not be a lasting storage solution.

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