Logic Pro is a great app and that's why there are bugs in every update release. Nevertheless the ones below seem to have been there for too long. Bug 1: Quick punch in pre recorded audio and midi tracks at the same time (replace mode) : .-In Logic 9 Previous midi notes keep sounding while recording new ones . The result after overdubing is a new region overlapping the previous passage. Old notes sound together with the new ones. . Behaving as in merge recording mode. .-In Logic X Previous midi notes keep sounding while recording new ones altough the result is correct when playing back after overdubing. Bug 2 : Quick punch on a pre recorder audio track. Punch-out is not as smooth as it should. There is a gap, like 2 sec of silence after punch out till the previous recorded track begins to sound. This doesn't happens in Logic 9 .Only in Logic X seems to be broken. Bug 3 : During pre roll using auto punch mode, there is not sound coming out from the track I want to Rec in. This happens both in logic 9 and X. Bug 4 Pre roll time behaves inconsistent depends on the playhead position when hitting record button. Sometimes ignores the pre roll number of bars, some times starts playing back far away from the punch-in locator ignoring pre roll preferences adjustmen. This also happens in both Logic 9 and Ligic X. Bug 5 Randomly, Punch-in on a prerecorded midi passage creates a new region with the new notes recorded during punch-in but it doesn't sound, I have to glue this "muted" region with the previos region in order to make it audible. It seems this only happens in Logic X. My Record preference settings: *Audio replace mode enabled (cycle/no cycle) *Midi replace mode enabled (cycle/no cycle) *Allow Quick punch-in checked *Input monitoring checked *Record/toggle enabled *Replace button in transport bar active. *Audio Track record enabled and highligted. *Midi track record enabled and highligted. My system: Mac Pro mid 2010, 2 x 2.4 GHz Quad-Core Intel Xeon,16 Gb ram. Mac pro bluilt in soundcard, no dedicate audio interface. Projects, Exs sampler files and audio files reside in a separate HD different from the OS X. In an attempt to rule out possible causes i have removed all third party plugins and reseted key commands unsuccesfully. Wonder if I should trash Logic preferences as well? Would apreciate if Logic Pro users could duplicate this behavior in their systems and let me know if they get the same result. Thanks in advance.