Teralo Drive

Teralo Drive puts your organisation's documents and your projects' document registers into Windows File Explorer, as an ordinary folder you can open, search, and drag files in and out of. It uses the same part of Windows that OneDrive uses, so a file takes no disk space until you open it. It is the same account and the same data as the web app, with the same permissions: nothing reaches your computer that you could not already open in Teralo.

It is off until somebody turns it on, and it is new.

Teralo Drive is Windows only

The drive is part of the Windows desktop app, and it has been tested on Windows 11. macOS and Linux get everything else the desktop app offers, including the desktop app and its Edit in desktop app action, but not the drive.

The app still marks the drive as in development. What it does, it does carefully, and the list of what it does not do yet is at the end of this article.

Two switches turn syncing on

They belong to different people and answer different questions, so both are needed.

Your organisation has to allow it. An administrator turns on Desktop editing in organisation settings. Absent means off: an organisation that has never seen the setting has not agreed to its documents being copied onto local disks. See Setting up your organisation.

This computer has to be signed in. In the desktop app, open Settings, then Desktop, and turn on Sync to this computer. Each computer signs in separately, and on a shared computer each person signs in their own.

Turning it on creates a folder called Teralo Drive in your user folder and adds it to Explorer's navigation pane, with one folder inside it for each organisation you have the drive on for.

What is in the Teralo Drive folder

Each organisation folder holds exactly two things.

Organisation is that organisation's Drive: its folders and its documents. You can write to it. Save into it, rename, delete, and create folders, and the change reaches Teralo.

Projects holds one folder per project, and each project's document register beneath it, arranged into the discipline and type folders the register already uses. These are read-only, because a register is decided in Teralo and never on a disk.

Register files are named for you, in the register's own scheme, so a file reads A110.03 Rev 48 - GA PLAN - GROUND FLOOR.pdf. A document with no revision drops the Rev part, and one whose discipline or type has not been set sits in a folder called Unclassified until somebody classifies it.

Each project also has an _Inbox folder, which is the one place under Projects you can write to.

Files are online-only, and download when you open them

Every file starts as a placeholder. It shows its name, its size and a cloud icon in Explorer, and it uses no disk space at all. Opening one downloads the whole file first, so a large model takes a moment the first time and opens straight away after that.

Keep a file on this device, or free up space

Explorer's own commands work as they do for any cloud folder. Right-click a file or a folder and choose Always keep on this device to download it and hold it, so it opens with no connection. Choose Free up space to hand the disk space back and leave the placeholder behind. In one measurement, freeing a 558 MB model returned 532.7 MB.

A file you asked to keep, which could not download because you were offline, is fetched once the connection comes back.

Add the Register columns to File Explorer

Project files carry five of the register's own columns, and Explorer hides them until you ask for them.

Right-click the column headings inside a project folder, choose More..., and tick these five.

They share the word Register so that they sit together in Explorer's alphabetical list, and because Windows already has columns of its own called Title and Status.

Dates in these columns read 2026-09-22, which is not the format Teralo uses everywhere else. Explorer sorts a column it does not own as plain text, and only that form of a date sorts into the right order.

Two things to expect. The columns belong to the whole drive, so they are blank on Organisation files, which have no register entry behind them. And they keep their last values while Teralo is closed, because it is Teralo that fills them in.

Project documents are read-only on your computer

You can open a register document, read it, copy it somewhere else and print it. You cannot rename it, move it, delete it or save over it, and you never will be able to. A register row carries a number, a revision, a discipline, a type and a status, and not one of those can be worked out from a file sitting on a disk.

If you clear the read-only attribute and edit one anyway, your work is not lost. The next time Teralo looks, it copies what you wrote into that project's _Inbox as <name> (edited on <computer> <date>) and sends it, and only then puts the register's own version back.

Send a file to a project through its _Inbox folder

Every project you can read has an _Inbox folder. Drop a file into it and it reaches Teralo as an unclassified document, in the same waiting bucket the web app shows as Temporary. Somebody then gives it a document number, a revision, a discipline and a type in Teralo, and it leaves _Inbox and appears in its proper folder on everybody's computer.

A drop is not a way into the register on its own. A filename carries no document number, so every classification field is left empty, and the only thing taken from the file is its name, used as the title. Nothing can be registered until somebody types a real document number.

A drop is always a new document. Nothing is overwritten and nothing can be deleted: a file you delete out of _Inbox comes back on the next pass. To get rid of an unwanted drop, delete it in Teralo, from the Temporary list.

The folder is shown for every project you can read, and is marked read-only where you do not have permission to upload documents to that project. It is shown rather than hidden so that "you cannot upload here" never looks like "this project has no inbox".

Nothing announces that a drop has arrived. The Documents module's Temporary tab counts what is waiting, and that count is the only signal there is. Tell whoever classifies documents that you have sent something.

Delete a file, and restore it from the trash within 30 days

Deleting a Drive document or folder does not destroy it, whether you delete it in Explorer or in the web app. It moves to the organisation's trash for 30 days, and is deleted for good only after that. A document takes its whole version history with it, and a folder takes everything inside it, in one action.

In Teralo, the Drive's Trash lists what was deleted, who deleted it, the full path it was in, and when it will go permanently. Restoring is one click and brings back exactly what that one delete removed, and nothing else that happened to be sitting in the trash underneath it. If the name was taken while the file sat in the trash, it comes back as report (2).pdf rather than not coming back.

Restoring and deleting permanently both need permission to delete Drive documents. Without it you can see the trash and press nothing.

Choose which projects are on this computer

Settings, then Desktop, lists every connected organisation's projects, all ticked. Untick one to take it off this computer, and tick it again to bring it back. The choice belongs to this computer, so unticking a project changes nothing for anybody else.

Unticking is refused while the project holds work Teralo does not have yet, and the page names up to five of the files that are holding it. Wait for them to send, or move them out of the folder, then untick again.

A project comes back online-only, as placeholders. Which of its files you had chosen to keep on the device is not remembered.

A project you are granted appears within five minutes. The Settings page asks for each organisation's project list once per visit, so a project granted while you have the page open shows up the next time you open it.

Nothing locks a document while somebody edits it

Two people can have the same document open, and the second save wins. That is exactly how uploading a new version in the web app already behaves, and the drive does not change it. Where two people are working on one document, agree between yourselves who has it.

Saving from File Explorer does not keep a version you can go back to

Saving a document in the drive uploads what you saved and moves the document on to its next version number. It does not keep the bytes it replaced. Ten saves from Explorer leave you at version eleven with no way back to any of the ten.

Uploading a new version in the web app behaves differently, and keeps what it replaced. Until this changes, use the web app for a save you might want to undo.

What a conflicted copy is, and why nothing was overwritten

Nothing is thrown away when the answer is unclear. Where a file changed on your computer and in Teralo at the same time, your copy is set aside beside the original as <name> (conflicted copy on <computer> <date>).<ext>, and becomes a document of its own on the next pass. Teralo's version keeps the original name.

Nothing is taken off your computer because a request failed, either. A network error, a server error, or any answer Teralo does not understand removes nothing at all. The worst that a confused answer can cost you is a download.

Losing access keeps the work you changed, in Kept files

When you are removed from an organisation or a project, or your permission is withdrawn, or an administrator turns Desktop editing off, the drive takes that organisation or project off your computer within a few seconds.

What you changed is kept. Files you never downloaded are removed, since they were only placeholders, and so are downloaded files that are provably unchanged, since Teralo already holds those bytes. Anything you changed, anything not yet sent, and anything the drive cannot account for stays on your disk. A lost project's files are carried out to Teralo Drive\Kept files\<organisation>\<project>\, keeping their place below the project.

You are told once, as a notification and as a line on Settings, then Desktop, which stays there until you remove the drive. It names the organisation or the project, how many files were kept, and where they went.

Getting access back picks up where it left off. A kept file whose document comes back unchanged is uploaded as an ordinary edit, with no conflicted copy and no restart.

Quit Teralo and the drive stops

Teralo moves every byte in and out of the drive, so the drive works only while Teralo is running. Quit it and nothing syncs, and a file that has not been downloaded cannot be opened until Teralo runs again. Closing the window is not quitting: the app hides itself in the system tray and carries on.

The first time you connect, Teralo turns on Start Teralo when you sign in to this computer, which starts it hidden in the tray. You can turn that off on the same page.

Turn Teralo Drive off

Turning Sync to this computer off takes every organisation folder off this computer.

• Files you had downloaded stay exactly where they are, as ordinary files, and so does Kept files.
• Files you had not downloaded are removed, because they were never really here.
• The folder leaves Explorer's navigation pane, and a Teralo Drive folder left empty is removed.
• This computer's sign-in is deleted, and start at sign-in is turned off.

Nothing is uploaded and nothing is deleted from Teralo.

What Teralo Drive does not do yet

• No upload progress. A large save reports that it is saving to Teralo and nothing more until it finishes.
• An interrupted large upload starts again from the beginning rather than from where it stopped.
• No version to go back to after a save from Explorer, and no history screen in the web app yet.
• No locking, as above.
• Nothing in the project tree except a drop. No renaming, moving, deleting or overwriting a register document from disk, by design.
• A computer left off for more than 30 days downloads the whole tree again rather than catching up.
• Revit models cannot be edited this way. Autodesk does not support workshared models in a synced folder, and a Revit local file is not one file that can be sent back. Download a copy instead.
• Word, Excel and Bluebeam have been proven; AutoCAD and saves above 50 MB have not. They may well work. They have not been put through a full round trip yet.
• macOS and Linux do not have the drive.

Guidance for IT departments

Everything below is per user. Teralo Drive needs no administrator rights, no machine-wide install and no package identity, and it has been tested on Windows 11 only. The desktop app's own deployment notes are in the desktop app.

Where it installs, and what it registers

The two processes are app.exe, the app itself, which Task Manager shows as Teralo, and teralo-sync.exe, the drive's sync engine. Both live in %LOCALAPPDATA%\Teralo. The app starts the engine and talks to it over standard input and output, with no listening port. The engine makes every request and serves every download that File Explorer or an application asks for, which is why quitting Teralo stops the drive.

The drive folder is %USERPROFILE%\Teralo Drive and cannot be moved. It sits outside Documents, so Known Folder Move does not touch it. Roaming profiles have not been tested.

Each organisation is registered as a sync root for the signed-in user through Windows' own StorageProviderSyncRootManager, which writes one key under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\SyncRootManager, created with full control for that user, and three navigation-pane entries under HKCU. The first connection also writes a Teralo value under HKCU\...\CurrentVersion\Run, which starts the app hidden.

The engine's sign-in is a Windows Credential Manager generic credential named sync-engine.Teralo Desktop Sync, saved with enterprise persistence. Its records and logs are in %APPDATA%\com.teralo.app\sync\, one log file a day, none deleted.

What to allowlist

Outbound HTTPS only. There is no inbound connection and no WebSocket, and the engine asks for changes every 30 seconds. It reaches two places.

• app.teralo.co, for the drive's API and for the engine's sign-in.
• Cloudflare R2, at *.r2.cloudflarestorage.com, directly. File contents download from and upload to it over short-lived signed URLs.

Its user agent is teralo-sync/<version>. TLS is checked against the Windows certificate store, so an inspecting proxy whose root certificate is deployed there works.

Also allowlist the executables under %LOCALAPPDATA%\Teralo. Note that AppLocker and WDAC default rule sets permit Program Files and the Windows directory and deny user-writable locations, which is exactly where a per-user install lives. In those environments the answer is an explicit publisher or path rule for Teralo, or the web app, which needs nothing installed.

Set a proxy where the drive cannot find one

The engine takes its proxy from the environment first, reading HTTPS_PROXY, HTTP_PROXY, ALL_PROXY and NO_PROXY, and then from the Windows proxy settings, meaning the proxy server set under "Use a proxy server" with its bypass list.

It does not read a setup script (a PAC file), automatic detection (WPAD), or WinHTTP's machine-wide proxy, all of which the app itself may follow. Where a proxy reaches the computer only in those ways, the app works but the drive cannot connect. Set HTTPS_PROXY for the user to the same proxy, through Group Policy Preferences for example, or set the proxy server explicitly, then restart Teralo. A proxy that requires authentication has not been tested.

Antivirus needs no exclusion, on the one scanner measured

Measured with Microsoft Defender, real-time protection on: a quick scan, a full scan and a custom scan of the drive folder downloaded nothing, so Defender needs no exclusion. No other scanner has been tested.

A scanner that reads online-only files during a scan downloads each one in full, which costs bandwidth and disk space but loses nothing. If one does, exclude %USERPROFILE%\Teralo Drive from its scheduled and on-demand scans and leave real-time protection on, which still scans a file as an application opens it.

Uninstalling deletes the drive folder and signs the computer out

Uninstalling Teralo deletes %USERPROFILE%\Teralo Drive and everything in it: downloaded files, Kept files, and any change that was never uploaded. Work has to reach Teralo to survive an uninstall. It also deletes the app's saved sign-in, so a reinstall starts signed out.

The drive is taken off first, through the engine, once Teralo has closed. The uninstaller then removes any key left under SyncRootManager with its navigation-pane entries, the Run values, and Teralo's notification settings. A file an application still holds open cannot be deleted, so it stays, with the folders above it.

To uninstall silently, run "%LOCALAPPDATA%\Teralo\uninstall.exe" /S. Never add /UPDATE, which is the updater's own switch: an uninstall run with it removes the program files but leaves the drive registered, the sign-in saved and the shortcuts in place. Never add _?= either, which marks an uninstall as part of an upgrade and keeps the Teralo Drive folder.

An uninstall leaves %APPDATA%\com.teralo.app, holding the engine's records and logs and any unsaved working copies, unless "Delete application data" was ticked. That box is unticked by default and is never shown in a silent or passive uninstall, which therefore always keep it. An uninstall also cannot revoke the engine's sign-in, which stays listed under Settings, Account, Connectors until somebody removes it; with its credential deleted from the computer, it can no longer be used.

Upgrade by installing over the top, never by uninstalling first

The app updates itself, and an update does none of the above: it stops the engine, installs the new version, and the drive carries on. A newer installer deployed silently with /S installs over the old version the same way.

Run interactively over an existing install, the installer offers "Uninstall before installing", selected by default. That runs the old version's uninstaller first, which takes the drive off and signs the computer out, though it keeps the Teralo Drive folder with every downloaded file handed back as an ordinary file. The other option upgrades in place, as an update does.

Never upgrade by uninstalling first. An upgrade that runs the old version's uninstall command and then installs the new one, which is what Intune or Configuration Manager supersedence with "Uninstall previous version" does, and what a winget UpgradeBehavior of uninstallPrevious does, is an uninstall as far as Teralo can tell. It deletes the Teralo Drive folder along with any change not yet uploaded. Supersede by installing the new version over the old one with /S instead.

Shared computers keep people apart

Everything is per user. Each account connects its own organisations, with its own folder, its own registration, its own credential and its own records, and nothing one account does reaches another's.