thank you for the responses.
I was using the classic bezier to 'trace' the curve from a .png image i had imported and scaled. It has happened about 20 times today(i believe this is the first time i have used the bz tools since updating). A couple of times i have been able to draw a curve or two before crashing other times it crashes before a line is completely drawn. I encountered this problem in trying to create the first face of a drawing so it is really not a large or complicated file by any means. i seem to be able to use fredoscale and other plug-ins and extensions fine. I did try disabling the bz tools in the plugin store tool, then quiting and re-enabling after re-starting without success.
I end up with the window saying a report will be sent to apple. the details are quite long - i could copy and paste them if this would help understanding the situation i happily would.
please let me know what other information would be helpful in resolving this situation.
thanks again