DC offset is an amplitude displacement from zero and appears not to be centered on the horizontal line. DC offset can cause clicks, distortion and headroom issues.
A simple trick to remove DC offset from a signal in Ableton Live is by using a High Pass filter on a very low setting. For example using EQ Eight and only use band 1 and set it to High Pass 1x or 4x at a frequency of 30 Hz and a Resonance of 0.71:
UPDATE: Live’s Utility also has a DC switch. Somehow I have forgotten about this. And the Saturator device has one (but it will saturate when the input is hot even with Drive at 0). So I guess using Utility in Live is the most simple trick to fix DC offset errors in Live.
For Propellerhead Reason users the MClass Equalizer is perfect, simply activate Lo Cut (30 Hz) and your signal is safe. 
Only an analog signal can contain DC offset. If it happens in software during processing it is a bug.
I would expect DAW systems to have an automatic DC offset fix but that’s not the case. Audacity mentions: “Newer Windows PCs may have a DC offset cancellation feature when recording from the built-in sound inputs.” That’s great news for Windows users.