Calibre is .epub default, but does not open on click
 

I've searched and I see some other issues with Calibre not opening, but that is not my problem.
I currently have 5.3 on Catalina MacOS and have for some time had as default for .epub, etc. For some time now, prior to 5.3 clicking on an .epub will not open Calibre, nor will right-clicking to open where it shows Calibre as default. All that happens is the Calibre icon in the tray bounces a bit.
Calibre opens fine otherwise, but I need to add books routinely while Calibre is open. This began several updates back, I'm unsure when.
Thank you.

Works fine on my mac. You can try either

1) Rename the calibre.app to calibre-other.app

if that works, then likely the issue is in launch services.

in which case

2) try clearing launch services cache/reset it

Kovid,
Many thanks for the quick reply.
I'm following the first part and at least grasp the idea.
But, a bit of a neophyte I'm a bit intimidated or confused about clearing launch services cache/reset it. I will be trying to get into it.

I did rename it, and the action was the same, the icon just bounced in the tray briefly as before. It was always working fine. I'm unsure when it stopped functioning. - I'm just now stumped as to how to proceed with the second part of your suggestion. Or, as the first part didn't work is the second part necessary, or is it something. Sorry, I'm just a bit confused about proceeded outside my skill. Thanks.

Kovid et al.
Sorry to be a nuisance. I've tried everything I can. A couple of utilities were recommended to me that did not help. It's clearly outside my skill set and could use a bit more hand-holding to step by step clear this up. Seems a minor issue that's just beyond me. Thanks very much

SOrry, not a macOS user, I cant give you more detailed instructions than that, from personal experience, however a bit of googling brings up: https://eclecticlight.co/2017/08/11/...nd-rebuilding/

Many thanks nonetheless Kovid. I appreciate your time and thank you. I didn't want to make work for you. I'll look into that as well as engaging some help from my son. Thanks again, especially for the marvelous Calibre.

Kovid, an update if I may.
I'm the last one to say "it's you not me", but I kept thinking to myself that this wasn't an issue until 5.0 - I got to thinking about my MacBook that had an old Calibre installed from some time back, but I never use it on that machine. It was v.3.44 - I grabbed a book, right-clicked, voila. Calibre opens. Now I update the Calibre to 5.3. The same book, right-click, just a little bounce in the tray by the Calibre icon but it won't open the program. So. What can I say? 5.0 was out a while ago. No one else has this problem on two machines but me? I'm not going to lose any sleep over this. I'll get along just opening Calibre first. Thanks for listening and once again thanks for this marvelous application.

For what its worth. It is working again in Big Sur.
I have no other explanation as I know numerous people developed the same issue in Catalina. I thought it might have been Calibre 5.5, but I had that before Big Sur.
Well, thanks for everything.

Did you reboot your your Mac ?

BR

BR, yes the devices were always rebooted and the problem persisted after v.5.0 - It was an issue on all of my devices, friends, and family. I haven't discussed it with anyone since Big Sur last week, but After updating to Big Sur, it's no longer an issue. I have no explanation for it. It was simply an issue from 5.0-5.5, no longer an issue after Big Sur.