3ds Max 2010 SP1 v64 bit
Krak 1.5.1.37938
I just ran into this today - the Krak File Birth and Krak File Update operators are no longer in the pflow depot. I opened a previous file that I had used these operators in and they behave and perform normally, but I don’t have a way to add them to a new file.
This is on purpose, since the Krakatoa File Birth/Update have been deprecated. Please use the Krakatoa PRT Birth/Update operators which are exactly the same, except they use PRT Loader objects to get the particles. This allows greater functionality, such as the ability to re-time sequences, use Krakatoa Channel Modifiers, etc.