KeyError: u'kind'

[senhal]

Hi, I get this error on opening an ebook with the reader:

calibre 2.59 Portable embedded-python: True is64bit: False
Windows-8-6.2.9200 Windows ('32bit', 'WindowsPE')
32bit process running on 64bit windows
('Windows', '8', '6.2.9200')
Python 2.7.9
Windows: ('8', '6.2.9200', '', 'Multiprocessor Free')
Successfully initialized third party plugins: Goodreads && Find Duplicates && Quality Check && Search The Internet && KindleUnpack - The Plugin && Modify ePub && Diaps Editing Toolbag
Traceback (most recent call last):
  File "site-packages\calibre\gui2\viewer\main.py", line 933, in load_ebook
  File "site-packages\calibre\gui2\viewer\ui.py", line 92, in show_opf
  File "site-packages\calibre\gui2\book_details.py", line 30, in render_html
  File "site-packages\calibre\gui2\viewer\ui.py", line 89, in render_data
  File "site-packages\calibre\ebooks\metadata\book\render.py", line 67, in mi_to_html
  File "site-packages\calibre\ebooks\metadata\book\render.py", line 67, in <genexpr>
  File "site-packages\calibre\ebooks\metadata\book\render.py", line 46, in get_field_list
  File "site-packages\calibre\ebooks\metadata\book\render.py", line 39, in displayable_field_keys
KeyError: u'kind'

I don't understand how to fix

[kovidgoyal]

The book has corrupted calibre specific metadata delete it the <mat name="calibre:... tags in the OPF file using the editor.

[senhal]

Perfect, thanks!