Synchronization and paired computers

FlyingFiles moves settings from one computer to another in two ways:

• with a file encrypted with a password — you save it on one computer and load it on the other, even one with a different system; you carry the file over yourself, e.g. on a USB flash drive;

• over the local network — with a computer you pair with this one once, with no file at all.

A paired computer can also share its files: you then open its drives in the panel like a local disk. Neither way goes through servers on the internet, and neither needs an account.

Everything is on the Synchronization tab of the File → Settings… window (on macOS also Cmd+,).

What synchronization transfers

In the What to synchronize section you choose the groups. All of them are selected by default; the OK button saves your choice.

These always stay on the computer: the window size, the panel folders and their history, column widths, the path to the FFmpeg program, disc templates and the Synchronization tab itself (the selected groups, paired computers and sharing).

Between different systems

• Paths inside the home folder — in favorite paths and in the SSH key files of servers and terminals — go to the home folder on the other computer. A favorite pointing to ~/Projects on a Mac leads on Windows to Projects in the user folder.

• Local favorite paths outside the home folder (e.g. /Volumes/NAS or D:\Data) and the font go only to a computer with the same system. Favorites pointing to FTP/SFTP servers go to any system.

• Keyboard shortcuts go from macOS to macOS, and between Windows and Linux both ways — these two systems have the same Ctrl shortcuts.

The app skips items that don't fit this computer and tells you about them below the list of changes.

Added, changed and removed

The app remembers when each item changed: a server, a terminal, a category, a favorite path, a single setting. When loading, the newer version wins. Removals are transferred to the other computer too, so a computer that was off for a long time won't bring back a server deleted on another one in the meantime. Changes made by hand in the settings.toml file are taken into account too.

When two computers already have their own, different settings, the first time you load, the items that differ are taken from the file or from the other computer — you can clear them in the preview of changes.

Moving settings with a file

Saving to a file

1. Open File → Settings…, the Synchronization tab, and in What to synchronize select what should go into the file.

2. Click Save to File…. Saving first applies the changes from the other tabs, just like OK; the Settings window stays open.

3. In the system's save dialog, choose a location. The app suggests a name with the computer name and the date — for the computer “Anna's MacBook Pro” it's FlyingFiles-AnnasMacBookPro-2026-10-05.ffsync. Only Latin letters without accents, digits, - and _ are kept from the computer name.

4. In the Settings File Password window, type the password in the Password: and Repeat password: fields. The password must have at least 8 characters; Show password reveals what you typed. OK works only when the password is long enough and both fields match.

5. A message gives the file and what it contains: the groups and the number of servers, passwords, terminals and favorite paths.

Below the buttons, the tab shows the time and file of the last save and of the last load.

Warning: The file's password cannot be recovered. Without it nobody can read the file — not even FlyingFiles.

macOS: When you save with server passwords, the system may ask for permission to read the Keychain. The first time, it may ask separately about each password saved by another version of the app. Choose Always Allow — after that, FlyingFiles uses its own encrypted copy of the passwords and asks at most once. A password the Keychain didn't release is skipped, and the app tells you how many there were; it doesn't go into the file and isn't deleted on the other computer.

Loading from a file

1. On the other computer, open the Synchronization tab and select the groups you want to take. Loading takes only the groups selected on this computer.

2. Click Load from File… and choose the .ffsync file. Loading also applies the changes from the other tabs first.

3. Type the file's password. After a wrong password, the window comes back with the message “Wrong password, or the file has been modified.”

4. Check the list in the Changes from the Settings File window (preview of changes) and click Apply.

A file from another program, or one saved by a newer version of FlyingFiles, is rejected before the app asks for the password. When nothing differs, instead of the list you'll see the message “The settings on this computer already match the file.”

Preview of changes

Before anything changes, the app shows the list of changes. At the top it says where the settings come from: which computer and system, when they were saved or fetched, and which version of FlyingFiles. The changes are grouped like the fields on the Synchronization tab, and each one has a checkbox and a kind:

Below the list are notes about what was skipped: groups not selected on this computer, items from another system, items from a newer version of the app, passwords skipped because the keychain was unavailable.

Apply (Enter) applies the selected changes: it saves the settings, passwords go to the keychain, and the appearance, language, server and terminal lists and keyboard shortcuts change right away. A message gives the number of changes applied. Cancel (Esc) closes the window without changing anything.

Pairing computers on the local network

Paired computers fetch settings from each other directly over the local network. You need:

• FlyingFiles 1.5.0 or later, running on both computers;

• one local network — both computers in the same subnet, connected by cable or over Wi-Fi (a VPN connection doesn't count);

• a firewall that lets the synchronization ports through, and on macOS permission to access the local network (firewall and permissions);

• on Linux — a working Secret Service keyring (GNOME Keyring, KWallet).

Pairing step by step

1. On both computers, open File → Settings…, the Synchronization tab, and in the Computers on the local network section click Pair a Computer…. The Pair Computers window shows the name and address of this computer.

2. The Computers with the pairing window open list shows the computers on the same network that have this window open: name, system and address. A computer paired earlier is marked “already paired”. Refresh searches again.

3. On one computer, click Pair next to the other one.

4. The other computer asks whether the computer at the given address may pair with it. Click Continue only if it's your computer and you're starting the pairing on it right now; otherwise click Decline. Both buttons become active after a second and a half, so that you don't click them by accident.

5. Both computers show Compare the codes and a six-digit code, e.g. 212 515. When the codes are identical, click Codes Match on both computers. When they differ — Codes Differ.

6. The window confirms: “Paired with “…””. Pair Another goes back to the list, Close closes the window.

The other computer isn't on the list? In the field below the list (“Don't see the other computer? Enter the address shown in its pairing window:”), type the IPv4 address from its pairing window, e.g. 192.168.1.20, or an address with a port, e.g. 192.168.1.20:28218, and click Connect. The app rejects an address outside this computer's local network.

• The code is made from the keys of both computers. Someone on the network impersonating the other computer would see a different code — that's why comparing the codes is the most important step. When the codes differ, try again in a moment; if it keeps happening, pair the computers on a different network.

• Each time you open the window, you get at most three failed attempts (successful pairings don't count), with a 3-second pause after each failed one. After the third failed attempt, close the window and open it again.

• Esc while the code is shown stops the pairing and goes back to the list. There's no Cancel button at this stage — it's there only while connecting and waiting for the other computer.

• The pairing window closes by itself after 10 minutes without pairing.

• You can pair at most 32 computers.

Paired computers on the tab

Each paired computer has its own row in the Computers on the local network section: its name, system, the pairing date, the time settings were last fetched from it and by it, the Share server passwords with it field, and the Synchronize Now and Unpair… buttons.

Unpair… (with a question, Cancel by default) removes the computer only from this list. On the other computer, this one stays until you remove it there too.

The Share this computer's settings with paired computers field is on by default. When it's off, this computer doesn't accept synchronization connections; it can still fetch settings from others itself.

Fetching settings from a paired computer

1. Make sure FlyingFiles is running on the other computer.

2. In that computer's row, click Synchronize Now. Like OK, this applies the changes from the other tabs.

3. The app connects to the last known address of that computer and at the same time asks for it on the network — in case the address has changed. Below the list you see what's happening (“Connecting to “…”…”, “Fetching settings from “…”…”). Stop or Esc stops fetching.

4. The Changes from “…” window opens — the same preview of changes as with a file. Click Apply.

Only the groups selected on both computers are transferred; the notes below the list say which groups the other computer doesn't share. On the other computer, the window title will say that settings were fetched.

Synchronize Now fetches settings from that computer to this one. To move them the other way, click Synchronize Now on the other computer. The app doesn't synchronize anything by itself in the background.

Server passwords

FTP/SFTP server passwords go over the network only to the computers you allow:

1. On the computer from which the passwords should go, select the Server passwords field in What to synchronize and click OK.

2. In the row of the computer that should get them, turn on Share server passwords with it and confirm with the Share button.

On the computer that fetches the passwords, the Server passwords field must be selected too. Password sharing is off by default for every paired computer. Turn it on only for your own computers — that computer will be able to fetch your server passwords.

macOS: Passwords saved in FlyingFiles are ready to share right away. Passwords saved or changed in another program — including another version of FlyingFiles — have to be read once with your permission: click Read Passwords from Keychain (the button is visible when you share passwords with some computer) and choose Always Allow. When the Mac you're fetching settings from skips passwords it couldn't read without asking, the preview of changes gives their number and points you to this button. On later launches of the app, macOS may ask for access to the Keychain — choose Always Allow then too.

Files of a paired computer

A paired computer can share its files. You then open its drives in the panel and work with them as with a local disk.

Sharing files

On the computer whose files you want to see, select the Share this computer’s files with paired computers field on the Synchronization tab and click OK. The field is off by default and doesn't depend on settings sharing.

Warning: Sharing covers all drives of this computer within the permissions of your account: a paired computer can read, write, rename and delete files. Turn it on only for your own computers. Turning the field off also stops a transfer in progress.

Working with the other computer's files

1. On the drive bar, after this computer's drives, there's a button with a monitor icon and the name of the paired computer. A long name is shortened; the tooltip shows it in full.

2. Clicking it opens the list of its drives in the active panel — the same ones it has on its own drive bar. The path field starts with the computer's name, e.g. MacBook Pro:/….

3. From there, everything that works on a local disk works here too: entering folders, preview (F3), editing (F4), copying (F5) and moving (F6), a new folder (F7), deleting (F8) and renaming. You can also copy between two paired computers opened in the two panels.

4. You get back to this computer's files with the button of its drive or of the home folder.

• A transfer has the usual progress window with a Cancel button, and there's no file size limit.

• An interrupted write — cancelling, a dropped connection, sharing turned off — doesn't damage the file at the destination: the previous version stays, and the unfinished copy is deleted.

• The other computer's drives themselves can't be deleted, moved or overwritten, and its button has no unmount or format menu.

• The app makes sure you don't move a file onto itself or copy a folder into its own subfolder — even when the same place on the other computer is visible under different paths.

The Show paired computers on the drive bar field (on by default) hides the computer buttons. It doesn't remove the pairing and doesn't turn off sharing. This field and Share this computer’s files with paired computers apply only to this computer and aren't transferred when settings are synchronized.

When something stands in the way, the app tells you what:

Firewall, ports and system permissions

• macOS: the first time you pair or fetch settings, the system may ask whether FlyingFiles may connect to devices on the local network — allow it. If you denied it, turn FlyingFiles on in System Settings → Privacy & Security → Local Network, then click Refresh in the pairing window.

• Windows: the Store package adds firewall rules for these ports by itself, during installation, and removes them when you uninstall. There's nothing to set up.

• Linux: Ubuntu and Debian have the firewall off by default, and the default zone of Fedora Workstation lets these ports through. If you turned the firewall on or tightened the zone, open the ports:

# ufw (Ubuntu, Debian)
sudo ufw allow 28217/udp && sudo ufw allow 28217:28220/tcp
# firewalld (Fedora)
sudo firewall-cmd --permanent --add-port=28217/udp --add-port=28217-28220/tcp && sudo firewall-cmd --reload

Linux: Local network synchronization and paired computers' files need a Secret Service keyring (GNOME Keyring, KWallet) with an unlocked collection — it holds the key that encrypts the pairings. Without it, the tab says that the synchronization key could not be read and turns this part off. After unlocking the keyring, click Try Again. Moving settings with a file keeps working; server passwords are then skipped with a message.

Security

• The .ffsync file is encrypted (AES-256-GCM) with a key derived from your password (PBKDF2-HMAC-SHA256, 600,000 iterations). Without the password nothing can be read — not the servers, not the computer's name, not the date it was saved — and a change of even a single byte shows up when the file is loaded. The suggested file name contains the computer's name and the date; you can change it when saving.

• Local network: each FlyingFiles installation has its own key. Pairing remembers the fingerprint of the other computer's key, every connection is encrypted (TLS 1.2 or 1.3), and both sides check that they're talking to the same computer as when they were paired. The app accepts connections only from the local network. Only a paired computer gets settings and files; an unpaired one can at most ask to pair, and only while the pairing window is open.

• Outside the pairing window, the app announces nothing about itself on the network; this computer's name then goes only to paired computers, over an encrypted connection.

• As long as you haven't paired any computer and haven't opened the pairing window, the app opens no synchronization ports and sends no announcements or queries to the local network.

More on how this works: How FlyingFiles works.

When something doesn't work