Several factors may cause skipping when you play audio or MIDI tracks in Ableton Live. However, the root cause almost always is a processor or disc overload. When Ableton tries to process too many audio elements at the same time, the resulting bottleneck causes the audio output to freeze intermittently, creating a skipping sound. To get rid of skipping in Ableton, install an ASIO driver for your soundcard, and render MIDI tracks to audio. Cropping audio tracks and loading them into RAM also can get rid of skipping.
Install an ASIO driver for your sound card. Steinberg's Audio Stream Input/Output standard is designed specifically for music production and reduces latency and skipping. Download the ASIO driver installer from your sound card manufacturer's website, if available. If not, download the universal ASIO driver from ASIO4ALL.com and install it. Set the "Driver Type" and "Audio Device" menus in the Ableton preference window to "ASIO," then adjust the buffer size and latency compensation settings until you hear the reduced skipping or none at all.
Render MIDI tracks to audio. The Virtual Studio Technology instruments, VSTis, that create sound from MIDI inputs can take up huge amounts of memory. Loading several large VSTis into the same set can cause audio skipping during playback. Right-click a MIDI track's name and select "Freeze Track." Play back the audio. If it continues to skip, right-click the track's name again. Select "Flatten" to converts the MIDI track to an audio track, which requires less processing power to play back. Only flatten MIDI tracks that require no further editing; once you've flattened a MIDI track to audio, you no longer can edit the MIDI.
Crop audio samples. Even if you're only using a small portion of an audio sample, Ableton keeps the entire sample loaded into memory. Cropping the sample removes the unneeded parts and reduces the memory footprint and processor load. Right-click a sample, then click "Crop." Save the set to remove the unused part of the sample from memory.
Load samples into RAM. By default, Ableton reads audio samples from the hard disk and streams them into the RAM as needed. This can cause skipping, especially if you're using samples located on an external hard drive or CD-ROM. To prevent this, load the entire sample into the system's RAM. Click on a sample, then simultaneously press "Shift" and "Tab" to switch to waveform view, if it's not already open. Click the "RAM" button in the "Sample" section to load the sample into RAM.