BassDaddy
This comes up about once a month. Never, instal from Service Center. Close it and install from the folders on your desktop. There is no way to reverse it. If you installed the sample libraries to a seperate hard drive you should only instal programs. You won't needti install libraries again.

Thanks for this. I was really confused. SC was set to download to C:\Programs\Native Instruments. I changed it to Downloads\Native Instruments (a folder I created in Downloads). I will install from there. I got things so messed up I had to completely re-install K10u. That is done and I am downloading the Absynth update now and will see it through before doing any more. What a mess but I suppose it will be worth it. Thanks, I searched NI updates and found this thread.
J

I also had some issues switching from Komplete 10 to Komplete 10 Ultimate.
From what I recall I ended up uninstalling all of Komplete 10 then reinstalling Ultimate.
I probably could've tried to resolve the various issues individually but it seemed to be the least painful solution going forward.  Granted you've got to install all that material again but the other issues (upgrading K10 plugin errors, etc.) evaporated and you're not going to get a surprise down the line when a new update appears. 
Aside from this the only issue I had with the Service Center was the old K3 plugins FM7, B42, etc staying activated.
 
In general I've found the best way to avoid or at least minimize issues with any VST installer is to

• Excluding VST3s - never assume that any installer system knows where your VST plugins are located.
• If possible specify separate locations for 32 and 64 plugins versions.
  Some companies use the same file name for both,
  some installers will have problems or lock up if you specify the same folder for both.
• Disable options to 'Delete files after successful install'
  Installers sometimes don't correctly interpret installation failures or you may need to reinstall at some point.

 
Best regards,
...Steven
 

OH... I just remembered, I need to make sure I have Rounds and something else... better go look.
Glad it worked for you. Some things are trial and error. I guess if you get every plugin ever made (like some people), you get pretty good at this sort of thing... IDK.
 
J