I've not used Z3ta+2 for a while but today when I open it in Ableton, I get the 'Thank you for purchasing this cakewalk product' dialog and asking me to re-enter my registration code. If I enter my code and click Complete, the dialog goes away and I can use it. If I then delete it in ableton and then open it again, I get the dialog come up again.
 
If the dialog pops up and I click quit, Z3ta still works and in the about box shows that I'm licensed to use it. This is very annoying and didn't used to happen. Maybe something has changed since I updated to the latest OS X (10.10.2) ?
 
I've tried reinstalling but that didn't make any difference?
 
HELP!!! 

Getting the same thing here.  Frustrating because I have a show coming up soon.

May want to contact Cakewalk support http://forum.cakewalk.com/FindPost/2090582 about this.

I'm getting this too.  Happened when I installed Logic 10.1.0  It screwed a bunch pf my plugins.  So they are screwed in Ableton Live as well. Had to reinstall all my Tone2 and Korg plugins. My Waldorf Edition is also asking for registration too, though it is worse because I have to reinstall it, then enter the registration.  Have to do this every time I want to use it. 

I have the same problem! I think this happened after upgrading to osx 10.10.2.
I've contacted the support five days ago ... without any answer yet!
 
EDIT: I have the same problem with Cakewalk CA-2A.

Same problem. Have contacted support. OSX 10.10.2 must've broken the registration system somehow.... sent a support email 5 days ago with no response. Very frustrating as I am using z3ta extensively in an album I'm working on as well as in my live show, so I can neither produce nor rehearse (nor play a show should the opportunity arise) until this is fixed.
 
I assume there is something of a panic going on at Cakewalk right now.... guess all we can do is wait for a patch.

Cerebral_Malfunction
I assume there is something of a panic going on at Cakewalk right now.... guess all we can do is wait for a patch.

They have been awfully silent so far.
 
The 10.1 update seems to have broken a lot of things judging from the traffic on the net.  Not just z3ta.
Maybe the problem lies with Apple.
 

I put it a ticket yesterday and had a reply first thing this morning. Known issue. The gentlemen at Cakewalk are working on a fix.
 
As for Waldorf Edition, I had the same problem when I upgraded computer - that was before Logic 10.1 came out. Contacted Waldorf and they pointed me to the latest installer which fixed the issue. I just checked and I have no problem w/ them in 10.1.

The same is happening to me. Hoping for a quick fix.

This is really incredible!!!! almost 15 days and no word from Cakewalk! No answer to my support request!!! How can someone rely on such a company???????
 
I already replaced all my instances of CA-2A for U-HE Presswerk and will never use Z3ta+ again! I will try to sell them as soon as this problem is solved and will never look back!