Calibre adding "data" folder containing an extra cover when I merge formats

GalacticHull · 12-11-2025, 07:22 PM

I've been using calibre for many years, and have never encountered what I describe in the title. It came about not with the current version, but when I installed the current version on a new computer. My guess would be this is a user-error issue. That I haven't ticked a box. Still, I don't recall this issue existing previously, and I've been using Calibre for over a decade.

The issue:

When I merge file formats, say a pdf and an epub, it creates a folder titled "data". In that folder it's nothing more than the cover image, named "cover-001.jpg"

Note also that in the Book Details column on the right, under Folders it says: Book Files, Data Files. The Data File is not the opf. It is the extra cover image.

If anyone could tell me what box to tick off to prevent this extra folder from being created, I'd appreciate it.

This is the most recent version of calibre running on windows 11, if that makes a difference.

Thank you kindly for any help

kovidgoyal · 12-11-2025, 10:00 PM

In the popup you get when you merge book uncheck the option to save alternate cover.

GalacticHull · Yesterday, 04:26 PM

Quote:

Originally Posted by kovidgoyal

In the popup you get when you merge book uncheck the option to save alternate cover.

Hi,

I do not get a pop up window when I merge books. I simply highlight both books, click M, and it merges them.

BetterRed · Yesterday, 04:41 PM

Quote:

Originally Posted by GalacticHull

Hi,

I do not get a pop up window when I merge books. I simply highlight both books, click M, and it merges them.

Have you disabled the "Are you sure" message for Merge. The option for saving the cover on the data folder was added fairly recently.

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There's a button in the Preferences->Behaviour to re-enable confirmation messages.

BR

12-11-2025, 07:22 PM	#1
GalacticHull Enthusiast Posts: 35 Karma: 10 Join Date: Nov 2014 Device: kobo h2O	Calibre adding "data" folder containing an extra cover when I merge formats I've been using calibre for many years, and have never encountered what I describe in the title. It came about not with the current version, but when I installed the current version on a new computer. My guess would be this is a user-error issue. That I haven't ticked a box. Still, I don't recall this issue existing previously, and I've been using Calibre for over a decade. The issue: When I merge file formats, say a pdf and an epub, it creates a folder titled "data". In that folder it's nothing more than the cover image, named "cover-001.jpg" Note also that in the Book Details column on the right, under Folders it says: Book Files, Data Files. The Data File is not the opf. It is the extra cover image. If anyone could tell me what box to tick off to prevent this extra folder from being created, I'd appreciate it. This is the most recent version of calibre running on windows 11, if that makes a difference. Thank you kindly for any help

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12-11-2025, 10:00 PM	#2
kovidgoyal creator of calibre Posts: 45,706 Karma: 28549304 Join Date: Oct 2006 Location: Mumbai, India Device: Various	In the popup you get when you merge book uncheck the option to save alternate cover.