Logic Pro/Logic Express: Error while trying to sync Audio and MIDI

The following error message may appear intermittently while playing:

"Error while trying to synchronize Audio and MIDI"

The basic issue when this happens is that Logic is either not getting audio data at the sample rate it expects, or the sample rate is fluctuating. Depending on the specific cause, here are some tips for resolving this:

  • In most cases, Logic can set the sample rate for the audio interface, but sometimes this is not possible. Check the sample rate for your audio audio interface and make sure it matches Logic's setting. If the settings match, try changing Logic's sample rate to a different setting and then back again.
  • If you have any devices digitally connected to the audio interface, make sure that only one device is set to be the master clock.
  • If you have combined multiple audio interfaces by configuring an Aggregate Device in Audio/MIDI Setup, make sure that the devices are digitally connected, and that only one device is configured as master clock.
  • If you are using Word Clock to sync multiple devices, be sure that all Word Clock connections are properly terminated.
  • Choose Audio > Audio Hardware & Drivers and try increasing the I/O Buffer size.
  • Try freezing tracks that use plug-ins that put significant load on the processor.
  • If you are running other software or hardware that can send MTC or MIDI clock, but intend for Logic to be the sync master, turn off Auto Sync In for Logic, to prevent Logic from receiving sync externally. The Auto Sync In setting can be accessed by click-holding the sync button on Logic's Transport.
  • If you are syncing Logic to another application or device via MTC, make sure that both Logic and the sync master are set to the same format. Make sure that Logic is not receiving both MIDI Clock and MTC. Also, configure the Audio Sync setting to "External or Free" in case the system is resolved to external Word Clock.
  • If you using a Reactor ensemble that syncs its LFO to the song tempo, try bypassing or removing the plug-in.
  • If none of the above helps, try switching to Built-in Audio. If this resolves the problem, check for updated drivers for your audio and MIDI interfaces.
Important: Information about products not manufactured by Apple is provided for information purposes only and does not constitute Apple’s recommendation or endorsement. Please contact the vendor for additional information.
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