Solution:
Ok to everyone that helped with this problem. I got it fixed.
I opened my MacKeeper/Default Apps/searched 'hxt'/ assigned AM to default app to open....BINGO!
Checked it in every version ALL WORKING.
So thank you to all of you for the help.
Well Rob I tried that created a new folder some place other than ver.19 folder, deleted old one picked new one...nope didn't work
So then I tried picking the folder from other versions....nope didn't work
Now thinking about the whole folder thing, If my memory is right in the HXT folder used to be just files like
xxxxxx.hxt
yyyyy.hxt
zzzzzzz.hxt
But now everything is in folders. Is that correct or am I just nuts.
Well an UPDATE....
I removed ver.19
Purchased a 1 year subscription of ver.19 , dowloaded and installed. (assuming a complete new install would fix problem)
Entered NEW activation code....opened up a model....
SAME PROBLEM...No Plugins, or Export...So guess I quit trying.....