Troubleshooting

Find the section below that matches your symptom. If nothing here fits, check the FAQ or contact support.

Diagnostic Logs #

FloSync keeps a log of every session. If you report a problem from inside the app, the recent logs are attached to your report automatically, so there is nothing for you to find or read.

If you want them yourself, use Help > Open Log Folder. Logs are kept for seven days.

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. Check the address

   • The URL field accepts https:// addresses, and assumes https:// if you type a bare address like example.com
   • If you paste an http:// address, FloSync won't accept it. Use the site's https:// address instead

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 a browser view
   • 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 Issues 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. The filename doesn't have to match, but the content does
   • If the videos aren't the same length, that computer won't follow the server's timeline. It keeps playing its own copy on its own instead

3. Firewall check

   • Allow FloSync through the firewall on both machines
   • Allow UDP 9201 for sync, and TCP 9202 on the server if you also import content from it

4. Server running check

   • Confirm the server icon (tower) in the top bar is lit in FloSync's bright lime highlight
   • Check that status bar shows "Server"
   • Try clicking the icon to stop and restart server mode

5. Version check

   • Both computers need compatible FloSync versions. A server running an incompatible version never appears in the list at all, and FloSync tells you once that it skipped it
   • Update both machines to the same version

6. 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: computers that run for days without a restart gradually drift apart from one another. This is a property of long-running computers rather than a fault in your setup, and it is why unattended installations are restarted on a schedule.

Solution: Restart both computers. For unattended installations, the sync optimization guide covers how to Schedule Regular Restarts during off-hours.

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 content loading

   • Go Live stays unavailable until at least one screen has content on it
   • Check for "File not found" indicators

3. Check Demo Mode

   • Fullscreen playback isn't available in Demo Mode, which uses virtual displays for screenshots and presentations
   • FloSync shows a warning if you try. Exit Demo Mode and go live again on your real displays

4. Check the mode you went live in

   • Controller mode is a different thing: it drives connected computers and deliberately opens no fullscreen windows on the machine you're sitting at. The status bar shows "Live (Controller)" in orange
   • If you wanted fullscreen windows here, stop and choose "Go Live (Current)" instead

Live Mode Stops on Its Own #

Symptoms: Fullscreen live ends without anyone stopping it, and a message says the display configuration changed.

Cause: FloSync stops fullscreen live when your display setup changes during a show, for example a screen is unplugged, switched off, or rearranged. Stopping cleanly is deliberate: continuing on a layout that no longer matches would put content on the wrong screens.

Solutions:

1. Check cables and power - a screen that drops out briefly counts as a change, even if it comes back
2. Reconfigure, then go live again - once the displays are back the way you want them, click Go Live
3. For permanent installations, keep screens on the same power circuit as the computer so nothing disconnects during quiet hours, and avoid display sleep entirely (see Optimizing for Sync)

ESC Key Doesn't Exit Live Mode #

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

Solutions:

1. Click the fullscreen window - a left-click on a live window exits live mode, exactly like ESC. If ESC isn't working, this is the fastest way out
2. Try the stop button - only reachable in Controller mode, where the control panel stays visible; click it there, labeled Stop Controller. In fullscreen Live or Schedule mode the panel sits behind the fullscreen windows and isn't reachable this way
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

   • If FloSync opens far enough to reach Preferences, use the reset below instead of deleting anything by hand
   • Otherwise delete ~/Library/Application Support/com.tentekio.flosync/ and relaunch FloSync

Windows Solutions:

1. Clear preferences

   • If FloSync opens far enough to reach Preferences, use the reset below instead of deleting anything by hand
   • Otherwise delete %APPDATA%\Tentekio LLC\FloSync\ and relaunch FloSync
   • If FloSync won't open at all, reinstall it

2. Reinstall Visual C++ Redistributable

   • Download latest from Microsoft

Resetting FloSync, on either platform:

Open Preferences, scroll to Danger Zone, and click Reset, the button beside Reset FloSync. Confirm with Reset & Quit. This clears your preferences, schedules, and content assignments, then quits, so relaunch FloSync afterwards.

Reset also deletes your logs. If you might send them to support, copy them out first with Help > Open Log Folder.

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 H.264 All-Intra for the best sync performance on all platforms. ProRes LT and DNxHR HQ are also supported alternatives, and both are available on macOS and Windows.

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
• Wi-Fi 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
• Display mode cannot be changed while in live mode (exit live first)
• Web pages cannot be spanned across screens (they display mirrored in Spanned mode)
• Web page addresses are entered as https:// URLs
• Network sync keeps video frame-aligned across computers; images and web pages don't have a synced position, but a scene change involving them still switches every computer at once
• The global canvas can't be imported between a Windows computer and a Mac. Configure it locally on each machine instead
• Seamless looping applies to MP4 and MOV files. Other formats use standard looping automatically

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