A while back I spoke with a customer regarding a strange issue he was having while using Logic Pro on his MacBook Pro. I was able to successfully help him based on the insight I had gained from having a similar issue myself.
The issue was related to an error message popping up while in the middle of recording one or many tracks, that reads: “System Overload” or “Disk is too slow”, followed by an error code. In addition to the error message, the track or tracks you were in the middle of recording would abruptly stop recording, halting any progress you had made. An extremely frustrating issue indeed, I needed to get to the bottom of this.
I had been using Logic Pro on my MacBook Pro for years without any issues. I use a multi-channel FireWire interface, and sometimes record up to 8 tracks at a time, flawlessly. I was baffled at how often this issue was happening now, considering I had never seen it before. My laptop had always been able to handle this load, no problem. Was there something wrong with my computer’s hardware? I hadn’t experienced any issues or abnormalities in anything outside of Logic, so my assumption was some configuration issue or glitch with Logic.
I researched some reliable forums, with no luck. I decided to start leaving the System Performance window open while recording, closely monitoring it. This window is very similar to the utility Activity Monitor, as it monitors your CPU/Ram usage on one meter, and disk bandwidth used on the other. I started noticing that right before the overload error occurred, I would have a massive spike in disk bandwidth. The only different variable from before, when I could record with no issues, was the environment in which I was recording. A small practice space in which I was right next to the source. This particular day we had decided to record bass. Loud, rumbling bass. My MacBook Pro was stationed about five or six feet from the hulking bass amp, on a hardwood, not very structurally sound, table.
At the time, I was not an Apple technician, however I was aware of the Sudden Motion Sensor built into my laptop, and how it worked. I grabbed the neoprene/foam sleeve I used, and placed it under my laptop (being careful not to obstruct the intake/outtake vents!), and attempted to record a dummy track, no errors. I tried a few more, just to confirm. The errors were gone! The vibrations coming from this bass amp had been just enough to kick the Sudden Motion Sensor on and park the hard drive heads, halting any hard drive activity, and causing an interruption in the recording.
Apple has since updated the error message, with the implementation on Logic 9.1.4, and issued a Support article, which can be found here: http://support.apple.com/kb/TS3834?locale=en_US
To learn more about the Sudden Motion Sensor in your laptop, Apple has a Support article here: http://support.apple.com/kb/HT1935?locale=en_US