[Fidney]

Hi,

I have used Calibre for several years with no issues.

I am using Calibre 2.49 (64bit) on Windows 10. All my books are in EPUB and MOBI formats, and most books I've got from Amazon is also in AZW3 format. I use calibre to create the additional formats after importing my book.

However, just recently I have started seeing the following error message:

calibre, version 2.49.0
WARNING: Error while saving: Failed to update metadata in some books, click "Show details" for more information

Failed to update the metadata in the EPUB format of: Destination: Void by Frank Herbert, with error:
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 373, in set_file_type_metadata
File "site-packages\calibre\customize\builtins.py", line 438, in set_metadata
File "site-packages\calibre\ebooks\metadata\epub.py", line 323, in set_metadata
File "site-packages\calibre\ebooks\metadata\epub.py", line 280, in update_metadata
File "site-packages\calibre\ebooks\metadata\opf2.py", line 1291, in smart_update
File "site-packages\calibre\ebooks\metadata\book\base.py", line 552, in smart_update
TypeError: coercing to Unicode: need string or buffer, list found


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Failed to update the metadata in the EPUB format of: Pride and Prejudice by Jane Austen, with error:
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 373, in set_file_type_metadata
File "site-packages\calibre\customize\builtins.py", line 438, in set_metadata
File "site-packages\calibre\ebooks\metadata\epub.py", line 323, in set_metadata
File "site-packages\calibre\ebooks\metadata\epub.py", line 280, in update_metadata
File "site-packages\calibre\ebooks\metadata\opf2.py", line 1291, in smart_update
File "site-packages\calibre\ebooks\metadata\book\base.py", line 552, in smart_update
TypeError: coercing to Unicode: need string or buffer, list found

It does not effect all titles, and I'm pretty sure it is something to do with my 5 custom metadata fields (Awards, Notes, Original Format, Source & Status) because if I create a new library with no custom metadata and copy books across before saving them to disc then I get no errors.

I had a different set of custom meta data fields until recently and in my last tidy up I removed some and added some new ones - I think I might have messed about too much and broken something!

Really grateful if anyone could let me know exactly what this means and if it is anything I should worry about.

Thanks in advance.