FileZilla Could Not Start Transfer: Fixes That Work

“Could not start transfer” in FileZilla usually means the connection, permissions, transfer mode, or server configuration is preventing a file from moving. Work through these checks in order to identify whether the problem is on your computer, network, or the FTP server; have your server login details and a small test file ready.

What You’ll Need

• FileZilla Client and the host, username, port, and connection type supplied by your hosting provider or server administrator.
• A small, non-sensitive file to use for testing, plus access to the destination folder if you need to check permissions.
• If possible, access to the server control panel or administrator who can check server logs and FTP settings.

Step-by-Step

1. Read the message in the transfer log. Select the failed item in the transfer queue, then review the messages in the Message Log above it. Look for the first failure, not just the final “could not start transfer” line. A timeout, authentication failure, permission denial, or connection refusal points to a different cause. If the log is hidden, enable it from the View menu.
2. Confirm the connection details. Open Site Manager and select the saved site. Compare the host name, port, protocol, username, and logon type with the details from your provider or administrator. Use the protocol they specify: FTP, FTP over TLS, or SFTP are distinct options and are not interchangeable. Do not guess a port or switch protocols at random. Re-enter the password if it may have changed, then connect and check the log for a successful login.
3. Check that the server is reachable. If FileZilla cannot connect at all, confirm the computer has internet access and that the host name is typed correctly. A server outage, maintenance window, or network rule may be stopping access. Ask the provider or administrator whether the server is available and whether your current public IP address is allowed. Avoid repeatedly retrying a blocked connection; it may trigger temporary restrictions.
4. Test with a simple path and a small file. In the remote site pane, navigate to a folder you are authorized to use. Try uploading a tiny test file, or downloading a known file to a local folder you can write to. Avoid starting with a large batch. If the test works, the original destination, file, or transfer size may be the issue rather than the connection itself.
5. Verify folder and file permissions. An account may be able to log in but lack permission to list a folder, create files, overwrite an existing file, or download from it. Try a permitted directory, or ask the administrator to check the account’s access rights and the destination directory’s permissions. Do not change broad server permissions yourself; use the minimum access required.
6. Check the local destination and file. For downloads, make sure the selected local folder exists, has free space, and is writable by your operating-system account. For uploads, confirm the local file still exists and is readable, and that another program is not moving or locking it. Close the failed queue item and add the transfer again after fixing the path.
7. Review transfer settings and queue state. In Site Manager, use the transfer mode recommended by the server; if none is specified, try the default setting first. For FTP, passive mode is commonly needed behind routers and firewalls, but the server must also be configured to support it. If the log reports that a data connection cannot be opened, ask the server administrator to check its passive-mode ports and firewall. Clear or remove only the failed queue entries, then retry one file.
8. Check firewall, VPN, and proxy interference. A firewall, VPN, proxy, or managed network can interrupt FTP data connections even when login succeeds. Check that FileZilla is allowed by your computer’s firewall and that the configured proxy matches your network. If permitted, briefly test another trusted network or disconnect a VPN, then restore your usual security settings. Do not disable firewall protection as a permanent fix.
9. Update and retest. Install FileZilla Client from its official download source and restart it. Reopen the saved site, reconnect, and send one small test file. If the problem remains, save the relevant Message Log lines and contact the server provider or administrator with the time of the attempt, protocol, and direction of transfer. Remove passwords, private keys, and other credentials before sharing logs.

Common Mistakes

• Confusing protocols: SFTP uses SSH, while FTP and FTP over TLS use FTP services. Selecting the wrong protocol or port can prevent a transfer even if the host name is correct.
• Changing many settings at once: This makes it hard to identify what helped. Change one setting, reconnect, and test a single file.
• Assuming login means write access: Successful authentication does not guarantee permission to upload, overwrite, or download from every folder.
• Trying to solve a server-side failure locally: If the server rejects a data connection or reports a permission issue, the provider or administrator may need to correct its configuration.
• Sharing credentials in screenshots or logs: Redact passwords, private-key material, tokens, and sensitive file paths before sending diagnostic information.

Tips

• Use Site Manager for saved connection settings, and keep a note of the provider’s exact protocol and port.
• Use the Message Log to distinguish a login problem from a data-transfer problem. The earliest relevant error is often the most useful.
• Test one small file in a known, permitted folder before retrying a large batch.
• When working with FTP through a firewall, ask the administrator which transfer mode and server data ports are supported rather than opening random ports.
• Keep FileZilla updated, and avoid saving passwords on shared or untrusted computers.

Troubleshooting

Login succeeds, but uploads fail: Check whether the account has write access to the destination and whether the server has available storage. Try a folder specifically provided for uploads. If the log mentions a data connection or timeout, have the administrator review passive-mode configuration and firewall rules.

Downloads fail but uploads work: Check read permission on the remote file and write permission and free space in the local destination. Try downloading a small file to a different local folder.

Only one file fails: Check that the file still exists, is accessible, and has a valid path and name for the server. A file that is already open or changing may also cause trouble. Retry it after confirming the source or destination is stable.

The error appears after a long pause: This often suggests a timeout or interrupted data connection. Test a stable network, check for VPN or firewall interference, and ask the server administrator whether there are connection limits or a service interruption.

You cannot tell what failed: Reproduce the problem once with a single small file, then copy the log entries from connection through failure. Share them with your provider or administrator, with credentials removed. Include whether you were uploading or downloading and which protocol you selected.

Frequently Asked Questions

Why can I connect but not transfer files?
Login and file transfer use different permissions and, in some setups, separate network connections. Check folder access and the server’s data-connection configuration.

Should I use active or passive mode?
Use the mode specified by the server administrator. Passive mode is often easier behind a router or firewall, but it still depends on the server allowing the required data connections.

Does “Could not start transfer” mean my password is wrong?
Not necessarily. A wrong password usually causes an authentication failure before transfer begins. Read the log to see whether login succeeded and what failed next.

Can I fix this by changing the port?
Only use the port supplied for the selected protocol. Changing it without server instructions can make the connection fail or connect to the wrong service.

What should I send to support?
Send the relevant Message Log lines, the time of the attempt, the selected protocol, and whether you were uploading or downloading. Redact passwords and other secrets.

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