Yes, in Kontakt go into Options, Memory, and uncheck Enable Memory Server and then restart Kontakt (or your host). Sounds like you figured it out. 😉 Glad it worked for you – I haven’t had any libraries behave like this before, but like I said, I’m no Kontakt “guru”.
I purchased Kontakt recently (and deleted my old less-than-legit version I’m happy to say). As much as I do not like Kontakt and NI’s somewhat stale Komplete bundle, I’d like to NOT miss out on certain amazing libraries/instruments such as these. In fact, I now own Komplete as well though it is not my favorite “piece of kit”.
I would love it if there were a Spitfire Labs type version of these PianoBook instruments (or even UVI Workstation) that doesn’t rely on Kontakt at all. Decent Sampler is okay but seems pretty, uh, “Spartan”. 😉 The main issue for me and I think lots of people these days is the UI size of Kontakt is not scalable and is TINY. On a 4K monitor it causes all kinds of problems trying to scale things and not ruin the look of your other stuff. On a multi-monitor setup, you can reduce the resolution of one just for older plugins but MAN what a PITA. Anyway, if NI would just UPDATE KONTAKT to address this (and help their library owners update their artwork to scale / etc), it would be GREAT and I for one wouldn’t be bitching about it.