sory for desinformation
this happens when book placed in subfolder in documents folder
CR3 can see the books in subfolder but after trying open it create 0 byte file in documents folder with same name and write that error
or maybe its because russian folder names, but mobi whith russian name opened normally from documents folder
with CR3 we need the mess of all books in one folder(
in any case, a big thanks for work, its already usable version