Spacebar works to preview on my MacBook Pro. What version of AE do you have? What version of OSX do you have?
Ok, interesting. I am using the newest AFX CC version 13.7, OS Yosemite 10.10.5
Maybe it is a collision between language packages? OS runs german, AFX runs in english.
Or any scripts or settings, that affect something?
I have the good old KeyEd Up script in use. With it I have changed shortcuts, because some english shortcuts do not work on a german keyboard.
Unless someone else has an idea, I'd suggest you contact Adobe support.
Yo dear community, if anybody has the same problem - the solution is to delete the user preference folder found in /Library/Preferences/Adobe/After Effects/13.x
Thx adobe support
Thank you for sharing what worked for you.