Error message on "Save to Disc"

[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


__________________________________________________ ____________________

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.

[BetterRed]

@Fidney - try this

• Backup the Library - and know how to restore it should need arise
• Then run Library Maintenance->Check Library and resolve any issues.
• If that doesn't fix it, run Library Maintenance->Restore Database. This can take a while, depends on number of books, speed of devices etc.

BR

[chaley]

Are you sending to a device when you see this problem?

Looking at calibre's code, that error implies that some custom column was "text, behaves like tags" but is now "text" (or vice versa), that the lookup key was reused, and furthermore that the book had its internal metadata updated using something like polish. The code paths are too complicated to know what changed or to guess further what the problem might be.

[Fidney]

Thanks for the replies BetterRed and chaley.

I tend to use the "Save to disc" option when I've changed the cover of the book as in most cases that seems to make my new cover stick without reconverting (which I don't like to do unless there is any other option). I save it to disc, delete from my library and then re-add it.

A couple of my custom metadata fields - Awards & Source - were created as "Text, column shown in the tag browser" but then I discovered option to create custom fields as "Comma separated text, like tags, shown in the tag browser" so removed them (I couldn't change the settings) and then re-added them.

I will back up the library as suggested and try to do some surgery on my custom metadata fields.

Good to know that I haven't irretrievably screwed something up.

Thanks for the help.

[eschwartz]

FWIW, use Embed Metadata or Polish Book in the future, rather than a song-and-a-dance with Save-to-disk.

Not sure that will help you with the error, but you should still do it.

[theducks]

You should never use STD to write INTO a Library.

As suggested, use polish


If Polish won't get the job done:

Use STD to save to a TEMP location.

Then drag and drop the updated book (format) into the DETAILS for that title.
This will REPLACE that format

[eschwartz]

theducks -- the OP was doing #3. I suggested #2.

STD == external embed.
Polish > embed on steroids.

Polish is ALWAYS enough.

[BetterRed]

Last time I looked Polish only operated on ePUB and AZW3 formats.

Embed will operate on other formats. Although I'm not sure if it can slap a cover on formats that don't have a designated cover - such as PDF.

BR

[eschwartz]

True enough that Polish works on less formats -- but when it does work, it is superior.

Embed will update whatever metadata is applicable to a format.
Polish will create a cover in EPUB or AZW3 if none exists yet.
MOBI doesn't support updating the cover.

[Fidney]

Thanks for your help folks. I have fixed my problem - probably took a long way round, but it worked!

I ended up deleting all my custom meta data fields then saving my entire library to disk. Then I created a completely new empty library (with no custom fields) and imported all my books into that.

Once they were all imported I could then add my custom fields and all works fine.

That done I would like to learn more about Embed and Polish. I presume thse are both Calibre plug-ins as I cannot find either of these within Calibre itself? Where can I find these two?

In Calibre when I click on "Get New Plugins" an error message box pops up saying "Unable to reach the plugin index page" and when I click on details all it shows is:
https://plugins.calibre-ebook.com/plugins.json.bz2
(is that normal or have I got another problem?)

In my browser I've tried going to the URL https://plugins.calibre-ebook.com which does take me ao a page with Calibre plugins but I can see neither of the above listed there.

Thanks again for the help and advice.

[BetterRed]

@Fidney - they are both built-in features - you can add them to toolbars and menus via Preferences->Toolbars.

BR

[theducks]

Calibre will not mess with existing toolbars. ( settings survive uninstalls)

So when a new feature comes along....
It just lurks ,
waiting for user intervention.

Read 'Whats new while your update download happens. Then go look for the new Icon in the toolbar configurator ( Editor and Viewer have their own configurators) when the install completes

[Fidney]

BetterRed & theducks

Thanks for that. I would never have thought about looking at the toolbars. Guess that's a lesson learned that I should at least have a nosey at the release notes from time to time!