Cyberduck is a remote-file browser that puts servers and cloud-storage accounts into a folder view. It connects through protocols such as SFTP, FTP, WebDAV, Amazon S3, Google Storage, and OpenStack Swift, then lets the user upload, download, rename, inspect, or share the remote objects. File Explorer can move local files, but it does not understand an SFTP host or an object-storage bucket without another connection layer. Cyberduck supplies that layer without mounting every connection as a permanent local disk.
Bookmarks hold context
A Cyberduck bookmark stores the protocol, host, username, starting path, and connection-specific choices. The server field expects a hostname rather than a web address with folders attached; the Path field holds the remote starting directory. Mixing those two parts can produce a valid connection that opens in the wrong place or cannot generate a usable web URL.
Credentials can stay in the operating system’s password store, while SFTP bookmarks can point to a private key. A saved bookmark is therefore more than a favorite link. Exporting its duck file shares connection settings, but the receiving computer may still need the password, key file, or client certificate.
Transfer choices
Cyberduck keeps uploads and downloads in a transfer window when it opens a dedicated transfer connection. That window remembers unfinished items after the program closes. Resume asks the server to continue an interrupted file; a server without resumable-transfer support makes Cyberduck reload it instead.
The existing-file action deserves attention before a large batch. Overwrite replaces the destination, Skip leaves it untouched, and Rename creates another copy with a changed name. Resume can append to an existing partial file when the sizes differ. Choosing one action as the default removes repeated prompts but applies the same destructive decision throughout the batch.
A bookmark can reuse the browser connection or open new transfer connections. Reusing it helps on a server that permits only one login, but the active transfer blocks browsing that connection. Multiple connections move several items concurrently, and segmented downloads split one file into parts. Both behaviors depend on server limits and can trigger waiting messages when the configured connection ceiling is reached.
Sync is deliberate
Folder synchronization compares modification times and checksums when the server exposes them. Mirror mode can create missing files on either side and replace the older copy. Download-only mode never uploads local changes, while upload-only mode never pulls remote changes. The confirmation list uses arrows and plus signs to show each pending direction before anything moves.
Timestamp preservation must be enabled for synchronization. Without it, date comparisons lose the information the decision relies on. Preserving timestamps or permissions can also slow large FTP uploads because Cyberduck must issue extra operations for many files.
Cyberduck does not watch a pair of folders continuously. The user must start synchronization again from the transfer window. Scheduled or unattended work belongs to the companion command-line interface or another synchronizing product, so closing the window does not create a background sync service.
Remote editing
File → Edit With sends a remote file to a temporary local directory and opens it in an external editor. Each save in that editor uploads the changed copy. Closing the document without saving leaves the server file unchanged. A delayed upload or disconnected session can still mean the editor has a newer temporary copy than the server, so the transfer result needs checking before that local copy disappears.
Encrypted vaults
Cyberduck can open Cryptomator-compatible vaults and encrypt data before it reaches the server. The remote provider sees encrypted names and content rather than the plain files. This protects stored data, but it adds a passphrase boundary: transfers require another passphrase entry unless the user saves the vault passphrase in the system credential store.
An older vault format may need migration in the Cryptomator desktop program before Cyberduck can open it. Copying encrypted vault files through an ordinary connection does not decrypt them, and losing the vault credentials leaves the stored objects unreadable.
