IMessage crashes my computer. I have to disable it to do anything

Question

for some reason my whole system crashes if I enable iMessage or face time on my iMac and Mac book pro. Its fine on my iPhone and iPad. I would love to use this service but it completely disables my system. After many hours of testing and trouble shooting, iMessage was the conflict.
Any advice would be greatly appreciated.

Answer 1

Hi,
So no Grey Screen with some text rolling down it first then an instruction to restart the Mac in different Languages ?  (Kernel Panic)
So error messages that pop up ?
No Pop ups with Logs to Send to Apple ?
Lets consider Fonts.
Most apps NEED Helvetica to be present and Enabled.  In the past with iChat there have been issues with Helvetica Fractions.
iChat and Messages also need Lucida Grande as this is used to title the Group Bars in the Buddy Lists.
It was found in Messages 8 in Mavericks that the app also needs the AppleGothic.ttf Font to be present and active.
It needs this Font when it registers the Apple ID and if you turn the app Off or the computer it seems the app re-registers the Apple ID each time you launch the app.
The AppleGothic.ttf font is in /Library/Fonts which is unusual as it is a required Font which are normally kept in /System/Library/Fonts (where the Helvetica and Lucida Grande ones are).
In Mavericks some people fond the font was Off using Font Book to look at it (it appears near the bottom of the list in this app).
Some found that Duplicating it in the Finder (File Menu) and then removing the Original and changing the duplicates name to the Orginal name also worked as did moving it to the /System/Library/Fonts location. (with a computer restart).
Do you have these Fonts Active ?
7:44 pm      Sunday; October 19, 2014
​  iMac 2.5Ghz i5 2011 (Mavericks 10.9)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
 Couple of iPhones and an iPad