After 5 years of productive use on several computers, I am suddenly unable to register this program on my new iMac 27. I just get an error message. Mind you, I have used these registration numbers on previous computers. Of course, the registration uses a "call home" system so registration depends on the developer staying in business and keeping that gimmick active. I have really a lot of stuff in this format and would, I guess, pay another ten bucks for a new license (not without a lot of complaining) if I had any confidence that buying a new license would solve my problem. The developer has been helpful before, but now is silent.
I am very concerned that TAO has been sold to some kind of reseller who is just trying to nab another $10 from registered users.