Ibooks BKAgentServiceErrorDomain error 8

Why does nobody from apple respond to questions on this topic. There are no answers here or in support and all over the net the same problem is discussed with no positive answer.

I have a library of several thousand books all of which no do not open having upgraded to High Sierra. All have the same error BKAgentServiceErrorDomain error 8 most of the solutions on the hundreds of discussion groups don;t work and others are just outright nonsense.

Why does Apple not address this directly. Three other post here concerning this issue have no response.

How do we fix this issue - please do not tell me to go to ~/librarycontain/blah blah blah as this does not work.

Does anyone - even an apple technician- have a solution for why the software does not work?