"Disk is too slow" in Logic Pro: the storage causes, and the settings that actually help
Logic stops playback when the drive cannot keep up. Often it is the drive itself, how full it is, or something else using it. How to tell, and what to change.
Playback stops and Logic shows Disk is too slow with a code in brackets, sometimes worded together with System Overload. Logic needs to read every audio track and write every recording in real time. When the drive falls behind, it stops rather than glitch.
Is it really the disk?
If the message mentions System Overload, it may be the processor, not the drive. Watch Logic's performance meters (the CPU and HD meters in the control bar). If the HD meter spikes when it stops, it is storage. If CPU cores max out, freezing tracks and raising the buffer helps more.
Storage causes, most common first
| Cause | Check | Fix |
|---|---|---|
| Recording to a spinning external drive | Get Info on the drive | Record to an internal or external SSD |
| The drive is nearly full | Free space under 10 to 15 percent | Make room or move the project. See a slow Mac with a full disk |
| Spotlight indexing the drive mid session | mds busy in Activity Monitor | Add the project drive to Spotlight's privacy list |
| Time Machine backing up the same drive | Time Machine icon animating | Pause it while recording |
| Sample libraries streaming from the same slow drive | Where your libraries live | Put libraries and projects on different drives, or both on SSD |
| A bus powered drive through a hub | How it is connected | Plug it directly into the Mac |
Settings that help
- Settings, Audio, Devices: raise the I/O buffer size while mixing. Lower it again only for recording.
- Freeze tracks with heavy plugins. Frozen tracks are rendered to audio files and read from disk, which costs less than processing live.
- Use File, Project Management, Clean Up to remove unused audio files, which reduces how much Logic has to track.
Space on the recording drive
Solid state drives slow down when they are almost full, because they have fewer free blocks to write into. A drive at 95 percent full can struggle on a session that ran fine at 60. Our guide to Logic and GarageBand sound libraries shows how to move Apple's sound content off the startup disk, which is often the quickest room to make.
See also audio projects taking up space.
Common questions
What does Disk is too slow mean in Logic Pro?
The drive could not read or write audio fast enough for real time playback or recording. Logic stops rather than produce glitches.
How do I fix Disk is too slow in Logic?
Record to an SSD, keep the drive well below full, stop Spotlight and Time Machine using it during sessions, raise the I/O buffer when mixing, and freeze heavy tracks.
Can a full drive cause Disk is too slow?
Yes. Solid state drives write more slowly when they are nearly full, and a session that worked at 60 percent full can fail at 95.