Calibre always opens the PDF file in FileManager instead of default application

shuvashish76 · 08-20-2026, 12:41 AM

When I click on PDF from Calibre's main window or click on View it opens up my Dolphin file-manager and shows the following dialog on top of the folder:

> Trying to open a file as a folder:'file:///home/shuvashish76/Calibre/Main/Author_name/Book_title.pdf'

from there (file-manager) if I click on the PDF it opens up my default Okular application.
I've already set "File Association" for PDF to open in Okular + Okular as default "PDF viewer" application from system settings.

[If I use Calibre's "Open with" external-plugin then it does work, so I guess something is misconfiguration on my side. Is it somewhat related file:// URI here?]

How to fix it so that it'll always open in my default application with Calibre's View option?

---

Device details:
- Calibre: 9.13 (isolated installation as instructed at official documentation)
- OS: EndeavourOS x86_64
- Kernel: Linux 6.18.44-1-lts
- DE: KDE Plasma 6.7.4
- WM: KWin (Wayland)
- Dolphin: 26.04.3

kovidgoyal · 08-20-2026, 09:32 AM

calibre doesnt open it, it passes it to Qt which in turn on typical linux systems passes it to xdg-open

shuvashish76 · 08-20-2026, 10:30 AM

Correct switched to WM: niri 26.04 (Wayland) for testing and works as expected.
Is it a bug for QT and better to report upstream? Is there any user-fix for KDE DE as user?

kovidgoyal · 08-20-2026, 10:31 PM

No idea I abandoned KDE decades ago. xdg-open is also very opaque and poorly designed. On my system I just wrote my own and put it in PATH ahead of the system one.

shuvashish76 · 08-21-2026, 12:37 AM

Anyway I was thinking to permanently switch to niri or hyprland wm. (kde as backup option)
ThankYou.

08-20-2026, 12:41 AM	#1
shuvashish76 Groupie Posts: 151 Karma: 1252294 Join Date: Jan 2022 Location: India Device: Kobo Clara BW	Calibre always opens the PDF file in FileManager instead of default application When I click on PDF from Calibre's main window or click on View it opens up my Dolphin file-manager and shows the following dialog on top of the folder: > Trying to open a file as a folder:'file:///home/shuvashish76/Calibre/Main/Author_name/Book_title.pdf' from there (file-manager) if I click on the PDF it opens up my default Okular application. I've already set "File Association" for PDF to open in Okular + Okular as default "PDF viewer" application from system settings. [If I use Calibre's "Open with" external-plugin then it does work, so I guess something is misconfiguration on my side. Is it somewhat related file:// URI here?] How to fix it so that it'll always open in my default application with Calibre's View option? --- Device details: - Calibre: 9.13 (isolated installation as instructed at official documentation) - OS: EndeavourOS x86_64 - Kernel: Linux 6.18.44-1-lts - DE: KDE Plasma 6.7.4 - WM: KWin (Wayland) - Dolphin: 26.04.3 Attached Thumbnails Last edited by shuvashish76; 08-20-2026 at 01:23 AM.

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08-20-2026, 09:32 AM	#2
kovidgoyal creator of calibre Posts: 46,449 Karma: 29634066 Join Date: Oct 2006 Location: Mumbai, India Device: Various	calibre doesnt open it, it passes it to Qt which in turn on typical linux systems passes it to xdg-open

08-20-2026, 10:30 AM	#3
shuvashish76 Groupie Posts: 151 Karma: 1252294 Join Date: Jan 2022 Location: India Device: Kobo Clara BW	Correct switched to WM: niri 26.04 (Wayland) for testing and works as expected. Is it a bug for QT and better to report upstream? Is there any user-fix for KDE DE as user?

08-20-2026, 10:31 PM	#4
kovidgoyal creator of calibre Posts: 46,449 Karma: 29634066 Join Date: Oct 2006 Location: Mumbai, India Device: Various	No idea I abandoned KDE decades ago. xdg-open is also very opaque and poorly designed. On my system I just wrote my own and put it in PATH ahead of the system one.

08-21-2026, 12:37 AM	#5
shuvashish76 Groupie Posts: 151 Karma: 1252294 Join Date: Jan 2022 Location: India Device: Kobo Clara BW	Anyway I was thinking to permanently switch to niri or hyprland wm. (kde as backup option) ThankYou.