Fix FileZilla Transfer Failed Errors

Complete guide to resolving file transfer failures

Common Transfer Error Messages

Error: Transfer failed
Error: Critical file transfer error
Error: Connection timed out after 20 seconds of inactivity
Error: Disconnected from server
Error: Connection closed by server
Error: File transfer failed after transferring X bytes

✓ Quick Fix: Retry the Transfer

  1. 1.
    Look at the Transfer Queue panel (bottom of FileZilla)
  2. 2.
    Find the failed transfer (shown in red)
  3. 3.
    Right-click the failed item
  4. 4.
    Select "Reset and requeue"
  5. 5.
    FileZilla will retry the transfer

Solution 1: Fix Connection Timeouts

Increase Timeout Settings

  1. Open Settings: Edit → Settings
  2. Go to: Connection
  3. Increase "Timeout in seconds": Try 60-120 seconds (default is 20)
  4. Click OK
  5. Retry your transfer

Longer timeouts help with slow servers or large files.

Enable Auto-Reconnect

  1. Open Settings: Edit → Settings
  2. Go to: Connection → FTP → "If connection lost"
  3. Check: "Retry" and "Reconnect and resume if connection is lost"
  4. Set retry attempts: 3-5 times
  5. Set retry delay: 3-5 seconds
  6. Click OK

FileZilla will automatically reconnect and resume failed transfers.

Enable Keep-Alive

  1. Open Settings: Edit → Settings
  2. Go to: Connection → FTP
  3. Check: "Send FTP keep-alive commands"
  4. Click OK

Prevents server from disconnecting during idle periods (like when transferring large files).

Solution 2: Check Transfer Mode (Passive/Active)

Transfer failures often occur due to incorrect FTP transfer mode (passive vs active).

→ Complete passive vs active mode guide

Quick Fix:

  1. Open File → Site Manager (Ctrl+S)
  2. Select your site
  3. Go to Transfer Settings tab
  4. Transfer mode: Select "Passive" (recommended)
  5. Click Connect
  6. If passive doesn't work, try "Active"

Solution 3: Configure Firewall & Antivirus

Windows Firewall

  1. Open: Windows Settings → Privacy & Security → Windows Security → Firewall & network protection
  2. Click "Allow an app through firewall"
  3. Click "Change settings"
  4. Find "FileZilla" in the list
  5. Check both "Private" and "Public" boxes
  6. If FileZilla isn't listed, click "Allow another app" and browse to FileZilla.exe
  7. Click OK

Antivirus Software

Antivirus can interfere with FTP transfers, especially with SSL/TLS.

Try these:

  • Disable "SSL scanning" or "HTTPS scanning"
  • Add FileZilla to antivirus exceptions/exclusions
  • Temporarily disable antivirus to test (re-enable after!)

Solution 4: Check Server Limits

📦 Disk Space Full

Error: "Critical file transfer error" or "Quota exceeded"

Solution:

  • Check server disk usage in hosting control panel
  • Delete old files to free up space
  • Upgrade hosting plan if needed

⚖️ File Size Limits

Many servers have upload size limits (e.g., 100MB, 500MB).

Solution:

  • Split large files into smaller chunks
  • Compress files before uploading
  • Contact host to increase limits
  • For PHP: increase upload_max_filesize and post_max_size

⏱️ Server Timeout

Some servers disconnect after inactivity (especially during large file transfers).

Solution:

  • Enable keep-alive commands (see Solution 1)
  • Request host increase server timeout
  • Transfer files in smaller batches

Solution 5: Reduce Simultaneous Transfers

Too many simultaneous transfers can overwhelm your connection or the server.

Adjust Transfer Settings

  1. Open Settings: Edit → Settings
  2. Go to: Transfers
  3. Maximum simultaneous transfers: Reduce to 1 or 2 (default is usually 2)
  4. Click OK

Why this helps:

  • Reduces bandwidth congestion
  • More reliable transfers on unstable connections
  • Less server resource usage
  • Easier to identify which file is causing issues

Solution 6: Fix Permission Errors

Error: Permission denied

You don't have write permissions for the destination folder.

→ Complete Permission Error Guide

Solution 7: Clear Transfer Queue

Sometimes the transfer queue becomes corrupted.

Reset Queue

  1. Stop all transfers: Right-click transfer queue → Stop and clear queue
  2. Close FileZilla
  3. Delete queue file:

    Windows:

    %APPDATA%\FileZilla\queue.xml
  4. Reopen FileZilla
  5. Start fresh transfers

Transfer Slow but Not Failing?

If transfers eventually succeed but are very slow, check out our speed optimization guide.

→ Speed Optimization Guide

Still Having Transfer Failures?

📋
Enable Debug Logging: Edit → Settings → Debug → Set to "Verbose" and check log file for details
🔄
Try Different Connection Method: Switch from FTP to SFTP or vice versa
🌐
Test on Different Network: Try from a different WiFi/ethernet connection
💬
Contact Hosting Support: Provide error messages and FileZilla logs

✓ Transfers Working Now?

Frequently Asked Questions

Why does my transfer fail randomly?

Random transfer failures are usually caused by unstable internet connection, server timeout settings, or firewall interference. Enable auto-reconnect in FileZilla settings and reduce simultaneous transfers.

Can I resume failed transfers?

Yes! Right-click the failed item in the transfer queue and select "Reset and requeue". FileZilla will retry the transfer from where it left off if the server supports resume.

What does "Connection timed out after 20 seconds" mean?

The server didn't respond within the timeout period. This can be due to slow server, network congestion, or firewall blocking. Try increasing timeout: Edit → Settings → Connection → Timeout.

Why do large files fail but small files work?

Large file transfers take longer and are more susceptible to connection drops, server resource limits, or upload size restrictions. Check server PHP upload limits and enable auto-reconnect.

Related Articles

Upload & Download Files

File transfer guide

Permission Denied

Fix file permission errors

Cannot Connect

Fix connection issues

Speed Optimization

Faster transfers

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