Free up app storage

Free up Outlook storage

Outlook stores mail in your Microsoft or other connected account. This phone keeps a local copy of recent messages, Focused Inbox cache, the Files tab downloads, and attachments you opened. Clearing cache does not delete mailbox mail. Emptying Deleted Items does.

See how much space Outlook is using

iPhone

1. Open the iPhone Settings app.
2. Tap General > iPhone Storage.
3. Tap Outlook or Microsoft Outlook.

Android

1. Open your phone Settings > Apps.
2. Tap Outlook.
3. Tap Storage or Storage and cache.

Attachments and the Files tab

1. Open Outlook and open the Files tab if you have it.
2. Remove large attachments you downloaded only for this phone, or delete the copies in Files / Downloads.

Opening an attachment can save a user file outside Outlook. Clearing Outlook cache does not remove that copy.

Sync window and images

1. Open Outlook > profile / Settings.
2. Look for sync duration, Download attachments, or image loading (labels vary by version).
3. Sync fewer days of mail if you do not need the full mailbox offline on this phone.

Older mail stays on the server. It is not deleted.

Focused Inbox cache

Focused Inbox is a view. The extra storage is still the same messages plus cache. Resetting cache (below) rebuilds Focused and Other. It does not empty the mailbox.

Deleted Items

Deleted mail goes to Deleted Items (or Trash). Emptying that folder permanently removes those messages from the account after any server retention. That is not cache.

Clear Outlook cache on Android

1. Open your phone Settings > Apps > Outlook.
2. Tap Storage or Storage and cache.
3. Tap Clear cache.

Do not tap Clear storage / Clear data unless you mean to sign out of every account in Outlook. Mail on the server stays. Drafts that never sent may not.

iPhone does not offer a separate Outlook cache button. Offload or reinstall after you save Drafts you still need.

Reinstall the app if storage is still high

If you already cleaned media and Outlook still looks huge, a fresh install can clear leftover cache and temp files that are hard to reach by hand.

1. Mail already on the server stays. Save Drafts and any attachments you downloaded only to this phone. Sign in again after reinstall.
2. Delete the app from your phone.
3. Restart your phone.
4. Install Outlook again from the App Store or Google Play.
5. Sign in and restore from backup if the app offers it.

This often frees a lot of space. You may need to download some media again after restore.

What to do next

After Outlook is lighter, check your photo library for duplicates and similar shots. That is what Dedupo is for.

More app guides: Free up app storage.