Clear Outlook Cache via Run: Safe Steps and Fixes

To clear Outlook’s local Auto-Complete cache in classic Outlook for Windows, close Outlook, press Windows+R, enter %localappdata%\Microsoft\Outlook\RoamCache, and press Enter. Delete the files inside the RoamCache folder, then reopen Outlook; this targets cached recipient suggestions, not every kind of Outlook data.

What the Run command clears—and what it does not

The Run command opens a folder in your Windows user profile. The RoamCache folder contains local Outlook roaming-cache files, including files associated with the Auto-Complete suggestion list. Clearing those files can help if recipient suggestions are stale, missing, or behaving incorrectly. Outlook may create new cache files as it runs again.

“Outlook cache” can mean several different things, though. People may be referring to recipient suggestions, an offline mailbox file, temporary form data, or data stored by the newer Outlook app. Those are not interchangeable. The Run path above is a targeted step for classic Outlook on Windows; it is not a universal command to erase all Outlook data or repair every Outlook problem.

Recipient suggestions: RoamCache is a relevant local cache location for classic Outlook.
Offline mailbox content: Usually stored in an OST file, which is separate from the RoamCache folder.
Account and message data: May be held on a mail server or in a local PST file, depending on the account and setup.
New Outlook: Uses a different app architecture, so classic Outlook folder instructions may not apply.

How to clear the RoamCache folder safely

Use these steps for classic Outlook for Microsoft 365 on Windows. If the goal is specifically to refresh Auto-Complete suggestions, this is the most relevant Run-based method.

Save any open work and close Outlook. Check that it has finished closing before changing its cache files.
Press Windows+R to open the Run dialog.
Type %localappdata%\Microsoft\Outlook\RoamCache and press Enter. The variable opens the Local AppData folder for the signed-in Windows account.
In File Explorer, review the files in the folder. If you are clearing the local Auto-Complete cache, delete the files inside RoamCache. Do not delete unrelated files elsewhere in the Outlook folder.
Reopen Outlook and try addressing a new message. Suggestions can take time to repopulate, and the old local suggestions may not all return.

If Windows says the location cannot be found, the folder may not exist for that Outlook profile, or the version or app you are using may store its data differently. Do not create a replacement folder just to follow the steps. Instead, use Outlook’s built-in Auto-Complete control if it is available, or identify whether you are using classic Outlook or new Outlook before trying another fix.

Use Outlook’s built-in option for Auto-Complete

If you want to empty recipient suggestions rather than troubleshoot a corrupted local cache, classic Outlook also provides a setting. In Outlook for Windows, go to File > Options > Mail. Under the section for sending messages, select Empty Auto-Complete List, then confirm. The wording and layout can vary slightly between builds.

This is often the clearer choice when you intentionally want to remove the whole suggestion list. Deleting RoamCache files is more useful as a local troubleshooting step, but it can have a similar practical effect on suggestions available on that computer. Neither method deletes messages from your mailbox. However, if your organization manages Outlook settings, policy or account synchronization may affect what returns.

Auto-Complete is also not the same as your address book. The address book or contacts list contains saved contact records; Auto-Complete offers names and addresses based on previous addressing activity. Removing suggestions should not be treated as a way to delete a contact. To remove an actual saved contact, edit or delete it in the contacts area of the relevant account.

Know the difference between RoamCache and an OST file

A common mistake is to delete every file in the Outlook folder because the word “cache” appears in troubleshooting instructions. An OST file is an offline copy of mailbox data used by supported account types when Outlook is configured for offline access. It is not the same as the Auto-Complete cache. Removing an OST can force Outlook to rebuild local mailbox data, which may take considerable time and use network bandwidth.

Before changing an OST, confirm that important mail and changes have synchronized with the server. A local-only change that has not synchronized could be at risk. PST files need particular care: they can contain locally stored mail, calendar items, or other data, and should not be treated as disposable cache files. If you are unsure which file is which, do not delete it. Use Outlook account settings or contact your organization’s support team rather than guessing based on a file extension.

For a mailbox synchronization problem, first check the connection and whether Outlook reports that it is working offline. Allow time for synchronization, and check the mailbox through its web version if available. If only one account or folder is affected, that detail can help narrow down whether the issue is local, account-specific, or server-side.

Classic Outlook, new Outlook, and Outlook on the web

The RoamCache instructions are intended for classic Outlook for Windows, the desktop program with the traditional File tab and Outlook Options window. They should not be assumed to work the same way in new Outlook for Windows. New Outlook is a separate app experience; its local app data and reset controls differ from classic Outlook’s profile folders.

For new Outlook, a Windows app reset is a possible troubleshooting option. In Windows, open Settings > Apps > Installed apps, find Outlook (new), open its advanced options if shown, and use Reset only when appropriate. Windows labels can differ by version. Resetting an app can remove local app data or require you to sign in again, so confirm that you know your account credentials and that important data is available from the mail service before proceeding.

Outlook on the web runs in a browser, so the Windows RoamCache path is not its cache-clearing method. Browser cache controls are managed by the browser, and clearing browser data can affect other sites or sign-ins. If the problem happens only in the browser, try a private window or a different browser as a diagnostic check before clearing broad browser data.

When clearing the cache can help

Clearing RoamCache is most relevant when classic Outlook repeatedly offers an obsolete address, fails to show expected recipient suggestions, or appears to have a damaged local suggestion cache. It is less likely to fix a password rejection, a server outage, a mailbox quota issue, or mail that is stuck because of a large attachment or connection problem.

For example, suppose Outlook keeps suggesting an old address for a colleague even after you type the correct one. If the wrong address appears as an Auto-Complete suggestion, removing the suggestion or clearing the relevant cache may help. If the wrong address is actually saved in Contacts, the cache reset will not correct that contact record. If messages to the correct address still fail, check the address and any delivery error rather than assuming the cache is responsible.

Try the least disruptive fix that matches the symptom:

For one unwanted recipient suggestion, remove that individual suggestion while composing a message, if Outlook offers the remove control beside it.
For a complete Auto-Complete reset, use Outlook’s Empty Auto-Complete List option.
For a suspected local cache problem, close classic Outlook and clear the RoamCache contents.
For account or synchronization errors, check connection status and account settings before deleting files.

Common problems and precautions

Outlook will not close: Wait for any send or synchronization activity to finish. If Outlook remains open, its files may be in use. Avoid deleting files while the application is running; close it normally first. If the app is unresponsive, use Windows Task Manager only as a last resort because ending a process can interrupt unsaved work.

The wrong suggestions return: A suggestion may be coming from another source, such as a saved contact, an organization’s address list, or synced account data. Clearing one local cache does not remove those sources. Check whether the entry is a contact or directory result before repeating the reset.

The folder is empty or absent: That does not necessarily mean Outlook is broken. The app version, profile, or account configuration may differ. Do not broaden the deletion to neighboring folders as a guess.

You use a shared or work computer: Removing cache files can affect the local Outlook experience for that Windows profile. Follow your organization’s support guidance, especially if the device is managed or Outlook data is subject to retention requirements.

Deleting RoamCache contents is generally less consequential than deleting mailbox data, but it is still sensible to keep the action narrow. Do not remove OST or PST files simply because they are in the same Outlook directory, and do not treat a cache reset as a backup or a guaranteed fix.

Frequently Asked Questions

What do I type in Run to clear Outlook cache?
For the local Auto-Complete cache in classic Outlook for Windows, press Windows+R and enter %localappdata%\Microsoft\Outlook\RoamCache. Close Outlook first, then delete the files inside that folder—not files elsewhere in the Outlook directory.

Will clearing Outlook RoamCache delete my emails?
Clearing the contents of RoamCache is intended to remove local cache files, not mailbox messages. Do not confuse it with deleting an OST or PST file; those files have different roles, and PST files can contain locally stored data.

How do I clear Outlook Auto-Complete without using Run?
In classic Outlook for Windows, open File > Options > Mail, choose Empty Auto-Complete List under the message-sending options, and confirm. This clears the suggestion list rather than deleting saved contacts.

Does the Run command work in new Outlook?
The RoamCache route is for classic Outlook and may not apply to new Outlook. For new Outlook, use its available app controls or Windows app settings; resetting the app may clear local data and require signing in again.

Should I delete my Outlook OST file to clear the cache?
Not as a first step. An OST is an offline mailbox copy, not the Auto-Complete cache. Confirm synchronization and the account type before considering any OST rebuild, and never delete a PST as a routine cache-clearing measure.

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