Issue:

During the HotFolder import, it throws the error message: Unknown error while opening E:\ABBYY_HotFolder\.....122060.pdf

Solution:

It is possible that the pdf file itself is corrupted.

To check, please open your pdf file in Acrobat Reader and scroll the pages down all the way to the last page. If during the scrolling and some error message occurs or the Acrobat Reader crashes, that means the pdf file is corrupted and FlexiCapture can't process the file.