Troubleshooting

This guide covers common issues you may encounter with FloSync and how to resolve them. If your issue isn't covered here, check the FAQ or contact support.

Diagnostic Logs #

FloSync maintains detailed logs that can help diagnose issues. These logs are invaluable for troubleshooting sync problems, understanding what happened during a session, or when contacting support.

Accessing Logs #

From the menu:

• macOS: Help > Open Log Folder
• Windows: Help > Open Log Folder

Manual location:

• macOS: ~/Library/Application Support/FloSync/logs/
• Windows: %APPDATA%/FloSync/logs/

Log Structure #

Logs are organized by date and hour:

logs/
├── 2026-01-19/
│   ├── 00.log    (midnight to 1am)
│   ├── 01.log    (1am to 2am)
│   ├── ...
│   └── 23.log    (11pm to midnight)
├── 2026-01-18/
│   └── ...

Log Retention #

Logs are kept for 7 days and automatically cleaned up when FloSync launches. This provides enough history for troubleshooting while not consuming excessive disk space.

What's in the Logs #

Logs include timestamped entries for:

• App startup and shutdown
• Video loading and playback events
• Sync events and corrections
• Network sync connections and disconnections
• Scene transitions during scheduled playback
• Errors and warnings

Using Logs for Troubleshooting #

1. Reproduce the issue - Note the approximate time when the problem occurred
2. Open the log folder - Use Help > Open Log Folder
3. Find the right file - Navigate to the date folder and open the hour log file
4. Search for errors - Look for entries marked "ERROR" or "WARN"
5. Review context - Read entries before and after the error for context

When contacting support, include the relevant log file(s) to help diagnose your issue faster.

Content Loading Issues #

Image Won't Load #

Symptoms: Dragging an image onto FloSync does nothing, or an error appears.

Possible Causes & Solutions:

1. Unsupported format

   • Supported formats: PNG, JPG/JPEG, GIF, BMP, TIFF, WebP, SVG
   • Check that the file isn't corrupted by opening it in another image viewer

2. File permissions

   • Ensure you have read access to the image file
   • Try copying the file to a local drive if it's on a network share

3. SVG limitations

   • Some complex SVG features may not render correctly
   • Try converting to PNG if the SVG doesn't display properly

Web Page Won't Load #

Symptoms: Web page shows blank or error in the screen.

Possible Causes & Solutions:

1. HTTP vs HTTPS

   • Only HTTPS URLs are supported (not HTTP)
   • Make sure your URL starts with https://

2. Network connectivity

   • Ensure you have internet access
   • Check if the website is accessible in a regular browser

3. Website blocks embedding

   • Some websites prevent being embedded in WebViews
   • Try a different website or use a local HTML file instead

Video Playback Issues #

Video Won't Load #

Symptoms: Dragging a video onto FloSync does nothing, or an error appears.

Possible Causes & Solutions:

1. Unsupported format

   • Try converting to MP4 (H.264) - see Video Codec Recommendations below
   • Check that the file isn't corrupted by playing it in another video player

2. Missing codecs

   • FloSync includes most common codecs, but some proprietary formats may not work
   • Convert to a standard format like MP4

3. File permissions

   • Ensure you have read access to the video file
   • Try copying the file to a local drive if it's on a network share

Video Stutters or Drops Frames #

Symptoms: Playback is jerky or not smooth.

Solutions:

1. Check CPU/GPU usage - If maxed out, your hardware may not handle the video resolution
2. Use SSD storage - Hard drives may not read fast enough for high-bitrate video
3. Lower video resolution - Re-encode at a lower resolution if hardware is struggling
4. Close other applications - Free up system resources
5. Check sync tolerance - If using sync, increase tolerance to reduce corrections

Screen Issues #

Second Screen Not Detected #

Symptoms: FloSync only shows one screen when multiple are connected.

Solutions:

1. Check OS display settings

   • macOS: System Settings > Displays
   • Windows: Settings > System > Display
   • Verify all screens are detected by the OS

2. Check cable connections

   • Try different cables
   • Try different ports on your computer

3. Restart FloSync after connecting new screens

   • FloSync detects screens on launch

Screen Arrangement Doesn't Match #

Symptoms: In Spanned mode, video sections appear on the wrong screens.

Solutions:

1. Configure OS screen arrangement

   • macOS: System Settings > Displays > Arrange
   • Windows: Settings > System > Display (drag to arrange)
   • Match the virtual arrangement to your physical setup

2. Restart FloSync after changing arrangement

Sync Issues #

Screens Out of Sync (Local) #

Symptoms: In Mirrored or Spanned mode, screens show different frames.

Solutions:

1. Wait for auto-correction - FloSync automatically corrects persistent drift
2. Check the status bar - During live mode, the sync corrections counter shows how many corrections have been made:
   • Low counts are normal over long sessions
   • Repeated or rapidly increasing counts can indicate a setup issue
3. Lower sync tolerance - Tighten sync tolerance in Preferences
4. Check the sync log - Look for drift warnings and corrections
5. Restart playback - Pause, then play again

Network Sync Not Working #

Symptoms: Client can't find server, or sync doesn't work after connecting.

Solutions:

1. Same network check

   • Both computers must be on the same local network
   • Verify by pinging between machines

2. Same video file

   • Clients must have the same video loaded
   • If video lengths differ, sync will fail

3. Firewall check

   • Allow FloSync through firewall on both machines
   • Allow UDP port 9201

4. Server running check

   • Confirm server icon (tower) is green in the top bar
   • Check that status bar shows "Server"
   • Try clicking the icon to stop and restart server mode

5. Wait for initial stabilization

   • Network sync may need a brief moment to settle after connecting
   • Some early corrections are normal
   • After settling, playback should remain stable and visually aligned

Gradual Sync Drift After Days of Uptime #

Symptoms: Network sync was working perfectly, but after several days of continuous operation, the client is persistently 50-100ms off and doesn't fully self-correct.

Cause: Every computer's system clock drifts at a slightly different rate over time due to hardware oscillator variance and temperature. After days of uninterrupted uptime, this accumulated drift can exceed what real-time clock correction can compensate for. This affects all clock-based synchronization systems, not just FloSync.

Solution: Restart both computers. For unattended installations, schedule a daily restart during off-hours — see Schedule Regular Restarts in the sync optimization guide.

Sync Corrections Cause Stuttering #

Symptoms: Video frequently jumps or stutters during playback.

Solutions:

1. Increase sync tolerance in Preferences
2. Check network quality (for network sync)
3. Reduce system load - close unnecessary applications
4. Check sync log for patterns

Go Live Issues #

Fullscreen Windows Don't Appear #

Symptoms: Clicking Go Live doesn't create fullscreen windows on screens.

Solutions:

1. Check screen detection

   • Ensure your screens are detected (they should appear in the screen arrangement area)
   • Try disconnecting and reconnecting screens
   • Restart FloSync after connecting new screens

2. Check video loading

   • Ensure at least one video is loaded before going live
   • Check for "missing video" indicators

3. Check permissions

   • On macOS, ensure FloSync has permission to control your computer (System Settings > Privacy & Security > Accessibility)
   • Try running FloSync as administrator on Windows

ESC Key Doesn't Exit Live Mode #

Symptoms: Pressing ESC on a fullscreen window doesn't exit live mode.

Solutions:

1. Ensure window has focus - Click on the fullscreen window first
2. Try the Stop Live button - Return to the control panel and click "Stop Live"
3. Force quit if necessary - Use Cmd+Q (macOS) or Alt+F4 (Windows) as a last resort

Application Issues #

FloSync Won't Launch #

macOS Solutions:

1. Security settings

   • Right-click FloSync and select "Open"
   • Or: System Settings > Privacy & Security > Allow FloSync

2. Clear preferences

   • Delete: ~/Library/Application Support/com.tentekio.flosync/
   • Relaunch FloSync

Windows Solutions:

1. Run as Administrator

   • Right-click FloSync > Run as administrator

2. Clear preferences

   • Delete: %APPDATA%\Tentekio\FloSync\
   • Relaunch FloSync

3. Reinstall Visual C++ Redistributable

   • Download latest from Microsoft

High CPU/Memory Usage #

Symptoms: FloSync uses excessive system resources.

Solutions:

1. Expected behavior - Video playback requires significant resources
2. Lower video resolution - Use 1080p instead of 4K if struggling
3. Reduce number of simultaneous videos - In Independent mode
4. Close sync log panel - Logging uses some resources
5. Check for runaway processes - Restart FloSync if resource use doesn't decrease when video is stopped

Video Codec Issues #

If you're experiencing sync drift or inconsistent playback when using network sync, your video codec may be the cause.

Quick fix: Transcode your video to ProRes LT (macOS) or DNxHD (Windows) for the best sync performance. If file size is a concern, H.264 All-Intra is a good alternative.

For detailed guidance on video formats, recommended codecs, sample files to test, and FFmpeg transcoding commands, see our comprehensive Video Preparation guide.

Known Issues #

Current Limitations #

• Spanned mode may not perfectly align at bezel boundaries
• WiFi network sync is less reliable than wired
• Some DRM-protected content cannot be played
• Very high-resolution video (8K+) may not perform well on all hardware
• Screen mode cannot be changed while in live mode (exit live first)
• Web pages cannot be spanned across screens (they display mirrored in Spanned mode)
• Only HTTPS URLs are supported for web pages (not HTTP)
• Network sync only works with video content (images and web pages are not synchronized)

Tips for Best Performance #

• Use wired network connections for network sync
• Keep content files on local storage (not network drives)
• Use consistent screen configurations across sessions
• Test your setup before critical presentations
• When using scheduling, test transitions with short time scenes first