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Hi,
Happy New Year.
Hope I am in the right place to get an answer.
When I try to open a .mobi book in Calibre, I get... 'calibre, version 2.46.0
ERROR: Could not open ebook: Unknown book type: '\x00\x00\x00\x00\x00\x00\x00\x00'

The complete error message is:
Traceback (most recent call last):
File "site-packages\calibre\gui2\viewer\main.py", line 37, in run
File "threading.py", line 763, in run
File "site-packages\calibre\ebooks\oeb\iterator\book.py", line 112, in __enter__
File "site-packages\calibre\customize\conversion.py", line 241, in __call__
File "site-packages\calibre\ebooks\conversion\plugins\mobi_in put.py", line 33, in convert
File "site-packages\calibre\ebooks\mobi\reader\mobi6.py", line 79, in __init__
MobiError: Unknown book type: '\x00\x00\x00\x00\x00\x00\x00\x00'

Is there any way I can get into the file to rectify the book type and what would I put instead of all the noughts? I tried Winrar and Winzip without success and changing from mobi to pdc didn't work either.

I'm on a PC with Windows 7.

Thanks for any help.