If FileZilla Pro suddenly won’t connect to a server you were using fine last week, and the only thing that changed is that the app updated itself, you’re not imagining it. It’s one of the most recurring patterns in our support forum: a working connection stops working right after an update, with no changes on the user’s side. This checklist walks through the specific failure modes we see most often on the desktop client, in the order worth checking them.
First, rule out the update as the actual cause
Before troubleshooting the update itself, it’s worth a quick sanity check — not every “it broke right after I updated” report turns out to be caused by the update. We’ve seen cases where the real trigger was a coincidental OS update, a change on the server side, or an ISP/network issue that happened to line up in time. A couple of quick checks:
- Can you connect to any other server from FileZilla Pro right now? If other sites connect fine and only one doesn’t, the problem is more likely specific to that server (or your network path to it) than to the update.
- Has anything else changed around the same time — a Windows or macOS update, a new antivirus/firewall rule, a VPN, a new network? FileZilla Pro updates and OS updates often land close together, and it’s easy to blame the wrong one.
If the problem really does look update-specific — it affects every server, or it started the moment the update finished — the sections below cover the patterns we see most.
Login or access errors that appeared right after updating
If a connection that used to log in cleanly now fails authentication or throws an access error immediately after an update, check whether any client-side setting quietly reverted to a default rather than assuming the remote server changed:
- Open the site’s entry in File > Site Manager and confirm the Logon Type, stored username, and protocol are still what you expect — in rare cases a stored password needs re-entering after an update.
- Check Edit > Settings > Connection for anything that looks reset to a default (encryption requirement, timeout values, passive/active mode) rather than your previous configuration.
- If you use a master password to protect your Site Manager entries, confirm you’re unlocking with it before connecting — a locked Site Manager can present as a plain connection failure.
If everything on the client side checks out and the server itself hasn’t changed, the next step is usually the server administrator or hosting provider, since an access error after a client update (rather than a connection or handshake failure) more often points to something on their end.
macOS: SSH key or Keychain integration stops working after an update
A pattern specific to macOS: SFTP connections that relied on a key stored in macOS Keychain, or on the system SSH agent, stop authenticating after a FileZilla Pro update — even though the key itself hasn’t changed.
This is usually a macOS permissions issue, not a lost or corrupted key. macOS treats an updated application binary as needing to re-confirm certain permissions, and Keychain access is one of them. To fix it:
- Open System Settings > Privacy & Security and check whether FileZilla Pro still has the access it needs (Full Disk Access, if you’ve granted it, is a common one to get silently reset after an update).
- Open Keychain Access, find the relevant SSH key entry, and check its “Access Control” tab — confirm FileZilla Pro is still listed as an app allowed to use it. If it isn’t, remove and re-add the permission rather than re-importing the key itself.
- In FileZilla Pro’s Site Manager, double-check the SFTP connection is still pointed at “Use system SSH agent” (or your configured key file path) and that the setting didn’t reset to a default during the update.
Connects fine, but directory listings or transfers fail
If the connection itself succeeds after an update but you can’t see remote files or transfers hang, that’s a different failure mode — usually something sitting between your computer and the server (antivirus, firewall, or a NAT router) rather than the update itself. Our Directory Listings and File Transfers Fail guide covers the full diagnostic steps. It’s worth ruling out alongside an update, but isn’t specific to one — the same checks apply whether or not you’ve updated recently.
Still being asked to update, or something looks like two versions at once
A related but different problem: if FileZilla Pro keeps prompting you to update even after you’ve just updated, or you’re seeing inconsistent behavior that suggests an old version is still around, that’s almost always a leftover duplicate install rather than a connection problem. Our How do I Fix Windows/MacOs Update Errors guide walks through finding and removing the older copy.
Still stuck?
If none of the above resolves it, two things will make support able to help faster: turning on full debug logging via How to Include Debug Information in the Message Log before reproducing the issue, and noting the exact FileZilla Pro version you updated from and to (Help > About). Then reach out via Contact FileZilla Pro Customer Support with the log attached — for connection issues specifically, the log is almost always what turns a guessing match into a fast fix.