Troubleshooting Guide

Every engineer encounters problems. The difference between a professional and an amateur is not whether problems occur—it is how quickly and calmly they are resolved. Use this guide as a quick reference when something goes wrong.

No Sound Output — You press Play and hear nothing. This is the most common studio problem.

• Check monitor power and volume. Are the speakers turned on? Is the volume knob up?
• Check the audio interface. Is it powered on? Are the output meters showing signal?
• Check Pro Tools: Setup → Playback Engine. Is the correct audio interface selected?
• Check Pro Tools: Setup → I/O Setup. Are the outputs correctly mapped?
• Check track routing. Is the track output set to the correct bus or main output?
• Check mute and solo. Is the track muted? Is another track soloed that is silencing this one?
• Check the operating system audio settings. On Mac: System Settings → Sound. On Windows: Sound Settings. Is the correct device selected as the output?
• Check cables. Swap the cable with one you know works.

If you still have no sound after all eight steps, try restarting Pro Tools, then the audio interface, then the computer—in that order.

Latency / Monitoring Delay — The performer hears a delay between singing/playing and what comes through the headphones.

• Reduce the H/W Buffer Size: Setup → Playback Engine. Lower the buffer (128 or 64 samples for recording). Smaller buffer = lower latency but higher CPU load.
• Enable Low Latency Monitoring mode (Options → Low Latency Monitoring). This bypasses plugin-induced delay on record-enabled tracks.
• Use direct monitoring from the audio interface (zero-latency monitoring). Most interfaces have a direct monitor knob or switch.
• Disable unnecessary plugins on the record-enabled track. Each plugin adds latency.
• Check if Delay Compensation is enabled (Options → Delay Compensation). This keeps all tracks aligned but can increase monitoring latency.

Rule of thumb: Set buffer to 128 or lower for recording, 1024 or higher for mixing.

Clicks, Pops, and Audio Dropouts — Random clicks, pops, or brief audio interruptions during playback or recording.

• Increase the H/W Buffer Size: Setup → Playback Engine. A buffer that is too small causes the CPU to fall behind.
• Check CPU usage: Window → System Usage. If the CPU meter or Disk meter is hitting the ceiling, you need to reduce load.
• Freeze or commit tracks with heavy plugins (Track → Freeze or Track → Commit).
• Close other applications. Browsers, email, and background processes steal CPU cycles.
• Check the audio interface drivers. Update to the latest version from the manufacturer.
• Disable Wi-Fi and Bluetooth during sessions—these can cause USB/Thunderbolt interference.
• Use a dedicated audio drive (SSD preferred) separate from the system drive.
• On Windows: Disable power management for USB ports (Device Manager → USB Root Hub → Properties → Power Management → uncheck “Allow the computer to turn off this device”).

CPU Overload / “DAE Error” — Pro Tools stops playback with a CPU overload error or DAE error.

• Increase buffer size to 1024 or 2048.
• Freeze or commit plugin-heavy tracks.
• Remove unused plugins (bypass is not enough—bypassed plugins still use some CPU).
• Reduce the number of active sends and buses.
• Convert virtual instruments to audio (print/bounce in place).
• Deactivate tracks that are not currently needed (right-click → Make Inactive).
• Check Setup → Playback Engine → increase the number of processing threads if available.
• If on a laptop, ensure it is plugged in and set to High Performance power mode.

Ground Loop / 60 Hz Hum — A persistent low-frequency hum (60 Hz in the US, 50 Hz in Europe) in the audio signal.

• Identify the source: disconnect devices one at a time until the hum disappears.
• Plug all audio equipment into the same power circuit/power strip.
• Use a DI box with a ground-lift switch on the offending device—it lifts the audio shield only; never defeat the AC safety ground with a cheater plug.
• Check all cable connections—loose or damaged cables cause hum.
• Keep audio cables away from power cables (cross at 90° angles if they must intersect).
• Use balanced cables wherever possible—balanced connections reject noise.
• If hum persists, use a hum eliminator (Ebtech Hum X or similar) on the offending device.

Phase Problems / Thin or Hollow Sound — Audio sounds thin, hollow, or loses low end when multiple mics or tracks are combined.

• Check microphone polarity. Flip the phase (polarity invert) on one of the conflicting channels using the Ø button on the preamp, console, or Pro Tools channel strip.
• Zoom in on the waveforms. If two waveforms are mirror images (one up when the other is down), they are out of phase.
• Check the 3:1 rule—microphones may be too close together relative to their distance from the source.
• Check for accidental cable wiring errors (pin 2/pin 3 swapped on an XLR cable).
• Use a correlation meter (available in many metering plugins). A reading below 0 indicates phase problems.
• Try time-aligning the tracks—zoom in and nudge one waveform to align with the other.

Plugin Crashes or Freezes — A plugin causes Pro Tools to crash, freeze, or become unresponsive.

• Update the plugin to the latest version.
• Update Pro Tools to the latest version.
• Check plugin compatibility—visit the developer's website for a Pro Tools compatibility chart.
• Remove and re-insert the plugin.
• Delete Pro Tools preferences: quit Pro Tools, then rename or delete the Pro Tools folder inside /Library/Preferences/Avid (Mac) or %appdata% Avid (Windows). Relaunch to regenerate fresh preferences.
• Open the session with plugins deactivated: hold Shift while clicking Open in the File menu. Every insert loads inactive; reactivate them one at a time (right-click the insert → Make Active) until the crash reproduces—that is your culprit.
• If Pro Tools will not launch at all, move your .aaxplugin files out of the Plug-Ins folder (/Library/Application Support/Avid/Audio/Plug-Ins on Mac, C: Program Files Common Files Avid Audio Plug-Ins on Windows) to a temporary folder, relaunch, then move them back in batches.
• Check for corrupt presets—reset the plugin to its default state.

Plugin License / iLok Errors — A plugin reports a missing license, or Pro Tools lists it as unauthorized at launch.

• Confirm the iLok USB key is connected, or that iLok License Manager is installed and running for machine/cloud activations.
• Open iLok License Manager and sync (File → Refresh). New purchases and renewals do not appear until the account syncs.
• Cloud-based licenses require an internet connection and time out offline—move the license to the machine or the USB key for sessions in rooms without reliable internet.
• Verify the license is actually activated in the developer's own account portal; some vendors require activation there before the license reaches iLok.

Corrupted Session / Session Will Not Open — A session crashes on open, hangs at the loading bar, or reports a corrupt file.

• Open the most recent auto-backup: inside the session folder, the Session File Backups folder holds timestamped .ptx backups. Sort by date and work backwards until one opens clean.
• Hold Shift while opening to load the session with plugins deactivated—a crashing plugin is the most common “corrupt session” impostor.
• Create a new empty session at the same sample rate and bit depth, then use Import Session Data (File → Import → Session Data) to pull the tracks across, leaving the damaged session structure behind.

Video Sync / Timecode Problems — Audio drifts out of sync with video, or timecode is not locking.

• Verify the session sample rate matches the video's audio sample rate (typically 48 kHz for video).
• Verify the session frame rate matches the video frame rate (23.976, 24, 25, 29.97, 30 fps).
• Convert interframe video (H.264/H.265) to intraframe (DNxHD/ProRes) before importing.
• Check the session start time (Setup → Session). By convention the program's first frame sits at 01:00:00:00, with the time before it reserved for pre-roll—tone, slate, and countdown.
• If using external sync, verify the leader/follower relationship and that all devices reference the same clock source.
• Re-import the video file. Corruption during transfer can cause sync issues.

Cannot Record / Track Not Arming

• Is the track record-enabled (the red R button is lit)?
• Check the track input assignment—is it set to the correct physical input?
• Is the audio interface input receiving signal (check the interface meters)?
• Is the microphone connected? Check cable, phantom power (if condenser), and preamp gain.
• Check disk space—Pro Tools cannot record if the drive is full.
• Check the session's record file type and bit depth (Setup → Session).
• Is the session in a read-only location? Sessions on read-only drives cannot record.

Quick Diagnosis Table — Remember the universal troubleshooting principle: change one thing at a time, test, and move to the next. Changing multiple variables simultaneously makes it impossible to identify the actual problem.