Free up Proton Drive storage

Proton Drive keeps files in your Proton account. This phone stores files you marked available offline, downloads you saved outside the app, and a preview cache. Clearing cache does not delete cloud files. Moving a file to Trash does.

See how much space Proton Drive is using

iPhone

Open the iPhone Settings app.
Tap General > iPhone Storage.
Tap Proton Drive.

Android

Open your phone Settings > Apps.
Tap Proton Drive.
Tap Storage or Storage and cache.

Account quota is separate: Proton Support says deleted files can take up to three hours to leave the quota, and Trash still counts until you empty it.

Remove offline files

Proton Support: offline copies stay encrypted inside the app. They are not the same as a Download saved to Files.

Open Proton Drive and tap the menu (☰).
Tap Available offline.
Open More (three dots) on a file or folder you do not need on this phone.
Turn off Make available offline if that option is there (wording can vary).

The file stays in Proton Drive. Only the copy on this phone is released. Open it later to download again.

Make available offline vs Download

Proton Support:

Make available offline caches the file inside Proton Drive (encrypted).
Download / Save to Files writes a normal copy on the phone.

Delete Downloads in Files. Clearing Proton Drive cache does not remove those copies.

Trash is not cache

Proton Support: More > Move to trash. Trash still uses Proton Drive quota until you empty it on drive.proton.me or in the app. That deletes account files, not just phone cache.

Clear Proton Drive cache on Android

Open your phone Settings > Apps > Proton Drive.
Tap Storage or Storage and cache.
Tap Clear cache.

Do not tap Clear storage / Clear data unless you mean to sign out. Cloud files stay. Offline copies and pending uploads on this phone do not.

iPhone does not offer a separate Proton Drive cache button. Remove offline files first, then offload the app in iPhone Storage if the system total stays high.

Reinstall the app if storage is still high

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

Files already in Proton Drive stay in your account. Finish uploads first. Offline-only copies on this phone are dropped until you mark them offline again.
Delete the app from your phone.
Restart your phone.
Install Proton Drive again from the App Store or Google Play.
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 Proton Drive is lighter, check your photo library for duplicates and similar shots. That is what Dedupo is for.

More app guides: Free up app storage.