We have 3 Macs OS 10.7.5, 16Gb and are all using Illustrator CC 2014. Since the Macs upgraded to CC 2014 all are exhibiting the same message, at random during deisgn, "Can't finish previewing. Could not complete the required operation.". At this point clicking on the "OK" button causes the screen graphics to appear in outline mode and unable to access / select any further commands, apart from "close".
Reverting back to the initial CC (which is still installed on the systems) shows no problems in completing the designs. Hence it appears that all the above issues seem apparent only since the latest CC upgrade.
Does anyone have any ideas as to this issue and any possible resolutions.