Mark a file or folder available offline and it opens from that device with no connection at all.

This is a different thing from the metadata cache. The cache remembers what a folder looked like so it reloads instantly and stays browsable offline; it says nothing about whether the bytes of any file are actually on the device. Offline availability is the promise that they are.

Marking something

Open the menu on any file or folder and choose Keep on this device. A badge appears in the tile's top-right corner once the bytes have landed.

The decision is device-local and never leaves the device. The same file can be kept on a phone and not on its owner's tablet, so there is no server-side flag and nothing to sync between devices.

Marking a folder cascades to its current contents, and stays a live preference rather than a one-time snapshot: anything added to that folder later is pulled down too, the next time the device is online, until you turn it back off.

Unmarking a folder removes what came down with it, and leaves alone anything you had marked individually.

Keeping it current

On reconnect the app compares each marked item's local checksum against the server's checksum_sha256 and re-downloads only what actually changed. It is never a blind re-fetch of everything marked.

The download itself goes through the same durable, resumable queue as every other transfer. Offline sync is not a second download path that has to be kept in step with the first one.

An item that has disappeared from the server, or that this account can no longer see, has its local copy removed rather than left behind as a private fork of something that no longer exists.

Space on the device

Settings, Downloads on this device shows what offline content is costing: the total, a breakdown by the folder each file came from, and a button to clear it all.

This is deliberately separate from the server storage screen. That number is about the server's disks; this one is about the phone or laptop in front of you, and someone looking at a nearly full device needs the second one.

There is a warning threshold, 2 GB by default. Going past it warns rather than refuses: telling you what something will cost is more useful than declining to keep a file you asked for. Set it to No limit to turn the warning off.

Browsing while genuinely offline

The folder tree renders from the metadata cache exactly as it does online.

Anything marked offline opens normally, from local bytes, with no spinner and no wait. Anything not marked still appears in the list, because you should be able to see what exists, with a plain "needs a connection" message instead of the usual preview and a button to keep it for next time. That state clears on its own the moment connectivity returns.

Where the bytes are

In the app's own support directory, under offline/, one flat folder keyed by node id.

Not a mirror of the server's folder names, deliberately. Two files in different folders can share a name, names change when someone renames a file, and a name can contain characters the local filesystem will not take. The id has none of those problems, and the device database already knows which id is which file.

Not available on web

A browser tab has no filesystem to keep bytes in, so the option is not offered there rather than offered and then failing. Everything else on this page applies to Android, iOS, Windows, macOS, and Linux.

Signing out

Signing out clears every offline copy, the metadata cache, and the transfer queue. The next person to use that device has no business seeing the previous one's folder names, let alone their files.