Every consumer cloud service ships the same thing: a sync client that copies your entire cloud onto every machine you own. That's a reasonable default when your cloud is 15 GB and your laptop has a terabyte. It stops being reasonable the moment those numbers invert — a 2 TB archive and a 256 GB SSD don't fit, and no amount of selective-sync configuration makes them fit comfortably.
WebDAV is the other answer, and it has been sitting in your operating system this whole time. Instead of copying files down, you mount the remote storage as a network location. Finder shows it in the sidebar, Windows gives it a drive letter, and the files stay on the server until something actually opens one.
This article covers what WebDAV does well, the three or four places it genuinely falls over, and how to connect it from macOS, Windows, Linux, Android, iOS, and the command line — using a credential you can revoke without touching your main password.
What WebDAV Is
WebDAV is an extension to HTTP that adds the verbs a filesystem needs and HTTP never had: create a collection, copy, move, lock, and read or write properties. It was standardised in 2007 as RFC 4918, which is why support is so widespread — WebDAV predates every proprietary sync protocol currently in use and it's a plain HTTPS conversation on port 443.
The practical consequence is that no client software is required. macOS, Windows, and most Linux desktops have a WebDAV client built into the file manager. Android and iOS reach it through free apps. Anything that speaks HTTP can be made to speak WebDAV, which is why rclone, backup tools, and CI scripts can all target it without a vendor SDK.
A mounted drive isn't a copy. Opening a folder issues a listing request. Opening a file downloads that file. Saving it uploads it back. Nothing else moves. A 2 TB archive mounted on a laptop occupies no local disk at all until you open something.
Sync Client vs Mounted Drive
These solve different problems, and most people want both — a sync client for the working set, a mount for the archive.
| Sync client | Mounted WebDAV drive | |
|---|---|---|
| Local disk used | The full size of what you sync | Effectively none |
| Works offline | Yes | No |
| Opening a file | Instant — it's already local | Downloads on demand; noticeable on large files over slow links |
| Conflicts | Yes, resolved by duplicating the file | None to resolve — there's only one copy |
| Software needed | A vendor client per machine | Built into the OS |
| Best for | Files you edit daily | Archives, media, backups, anything larger than your disk |
The conflict row deserves emphasis. Sync clients produce files like report (John's conflicted copy 2026-06-14).xlsx because two machines edited the same local copy and the server had to keep both. A mount can't produce that, because there was never a second copy — you're editing the file on the server.
Device Passwords, Not Your Account Password
Your dashboard password opens billing, domains, mailboxes, and the account itself. Typing it into a backup script, a file manager on a phone you might trade in, or a laptop that could get left in a taxi is a risk with no upside.
Drive uses a separate credential per connection — a device password, generated on the Sync devices page, shown once, and stored only as a hash. Three properties matter:
- Independent revocation. Revoke the laptop and every other device stays connected. There's no reset cascade and no re-pairing of the things you didn't lose.
- Scoped permissions. Each password carries the rights you pick when you create it. A read-only password on a phone can browse the archive but can't delete anything by accident. A backup script gets write access to Drive and nothing else — it can't see billing, domains, or mail.
- Never recoverable. Only a hash is stored. Lose the password and you generate a new one; nobody, including us, can read the old one back.
Every client needs the same three values, whatever it calls them: the server URL from the Sync devices page, your account email as the username, and the dsync_ device password. Details are in Sync devices.
Connecting From Each Platform
macOS Finder
Go → Connect to Server (Command + K), paste the server URL, connect as a Registered User, and enter your account email and device password. The drive appears in the Finder sidebar and mounts automatically at login if you save the credentials to Keychain. Nothing to install. Full walkthrough: Finder on macOS.
Windows File Explorer
Right-click This PC → Map network drive, pick a letter, paste the URL, tick Connect using different credentials, and enter the same email and device password. It shows up under This PC alongside your local disks. Read the 50 MB trap below before you move anything large. Walkthrough: Windows Explorer.
Linux
GNOME Files and KDE Dolphin both accept a davs:// URL in the location bar and will prompt for credentials. For a mount that behaves like a real filesystem to every application, davfs2 works, though in practice rclone mount is faster and easier to tune.
rclone (any platform, scriptable)
The right tool for anything unattended: backups, scheduled sync, and multi-terabyte transfers. Configure a WebDAV remote with vendor other, then use rclone sync, rclone copy, or rclone mount as needed. rclone's WebDAV backend uploads in parallel, retries on its own, and has no file-size ceiling. Setup: rclone.
Cyberduck (macOS and Windows)
Free, graphical, and considerably better than either OS file manager at moving large files. Cyberduck splits the URL across separate Server and Path fields — use protocol WebDAV (HTTP/SSL), never the plain HTTP variant. Setup: Cyberduck.
Android
DAVx⁵ registers the mount with Android's Storage Access Framework, which means Drive then appears as a storage location inside Files by Google, Solid Explorer, Total Commander, and anything else that uses the standard picker. Setup: DAVx⁵.
iOS and iPadOS
Documents by Readdle adds the mount and exposes it through the system Files app, so it's available to any app that opens a document. Setup: Documents on iOS.
The Windows 50 MB Trap
Windows' built-in WebDAV client refuses transfers over roughly 50 MB and reports it as a generic network error, which sends people looking for a server problem that doesn't exist. It's a Microsoft default in the WebClient service, unrelated to whatever server you connected to.
The registry value is FileSizeLimitInBytes under:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\ParametersSet it, in decimal, to 4294967295 — about 4 GB, which is the highest Windows accepts — then restart the WebClient service or the machine. For anything above 4 GB, use rclone or Cyberduck; both bypass WebClient entirely and have no such ceiling.
While you're there: Windows' WebDAV client transfers serially, one chunk at a time. It's fine for opening documents and poor at bulk transfer. If you're moving a lot of data on Windows regularly, do it through rclone and keep the mapped drive for casual browsing.
Large Files
There's no file-size cap on the TrekMail side. Uploads are chunked and resumable, so a transfer that drops at 80% continues rather than restarting. The ceilings you'll actually encounter belong to the client:
| Client | Practical ceiling |
|---|---|
| Windows Explorer | 50 MB by default, ~4 GB after the registry change |
| macOS Finder | No hard cap; gets slow and stalls on very large files |
| Cyberduck | None in practice |
| rclone | None; parallel and resumable |
The pattern that works: mount the drive on desktops for browsing and everyday documents, and script rclone for anything measured in gigabytes.
Where WebDAV Falls Down
No offline access. This is the fundamental trade. No local copy means no access on a plane. If you need a file offline, download it first, or keep that particular folder in a sync client instead.
Latency shows up in applications that assume a local disk. Opening a 200 MB video from a mounted drive downloads 200 MB. Photo libraries, database files, and anything that does thousands of small random reads will feel bad over WebDAV. Copy those locally, work, copy back.
Office file locking is imperfect. Word and Excel can open and save directly to a mount, but the lock files they create over WebDAV are less reliable than on a real network share. Two people editing the same spreadsheet simultaneously won't be warned as consistently as they would on SMB.
Directory listings cost a round trip. A folder with 10,000 files in it will take a moment to open. Nesting into subfolders isn't just tidier, it's measurably faster.
Deletes go to Trash, not into the void. Deleting from a mounted drive moves the file to Drive's trash, where it's restorable for 30 days. This is usually what you want, and it does mean freeing space requires emptying the trash. See Trash and restore.
WebDAV is not a way to send files to other people. It's an access protocol for storage you own. To get a file to someone outside the account, generate a share link instead — and if you're currently emailing large files around, email plus file sharing covers why that stops working above about 18 MB.
Which Client to Use
| You want to… | Use |
|---|---|
| Browse and open documents on a Mac | Finder |
| Browse and open documents on Windows | Mapped network drive (after the registry fix) |
| Move many gigabytes, or anything scheduled | rclone |
| Move large files by hand, with a UI | Cyberduck |
| Reach the archive from a phone | DAVx⁵ on Android, Documents on iOS |
| Back up a server nightly | rclone with a write-scoped device password |
Frequently Asked Questions
Do I need to install anything?
Not on macOS, Windows, or most Linux desktops — the WebDAV client is part of the OS. Mobile needs one free app: DAVx⁵ on Android, Documents on iOS. rclone and Cyberduck are optional and worth having if you move large files.
Does mounting use my local disk?
Only for temporary caching of files you open. A 2 TB Drive mounted on a laptop with a 256 GB disk works fine, because nothing is downloaded until you open it.
Why a device password instead of my normal one?
So you can revoke one machine without disturbing the others, and so a credential sitting in a config file grants file access only — not billing, not domains, not mail. Device passwords are also scoped: a read-only one can't delete anything.
What happens if I revoke a device that's currently connected?
The next request from that machine fails authentication and the mount drops. Transfers in flight stop. Nothing is deleted and no other device is affected.
Can two people mount the same folder?
Yes. Folders shared with the account are visible to every mailbox in it, and each person connects with their own device password. Simultaneous edits to the same file are still last-write-wins, so coordinate on shared documents. See sharing folders with your team.
Is WebDAV encrypted?
The connection is HTTPS on port 443, so everything in transit is encrypted with TLS. Never configure a client with the plain http:// variant — in Cyberduck specifically, that means picking WebDAV (HTTP/SSL) rather than WebDAV (HTTP).
Can I use this for automated backups?
Yes, and rclone is the tool for it. Generate a device password with edit permission, keep it in the environment rather than the repository, and schedule rclone sync. Because the password is scoped to Drive, a compromised backup host can't reach the rest of the account.
