Please check your Lightroom should be up to date to the latest release.
Also, you try and reset the Lightroom preferences back to default.
You need to restart Lightroom, and then hold down the Shift and Option keys on Mac, or the Shift and Alt Keys on PC. The Reset Preferences dialog appears.
Choose Reset Preferences to reset
Let us know if that helps.
Up to date, Reset preferences, and no change in the way it was performing.
UPDATE>>> I cancelled the backup operation, when I posted my first reply... It still hasn't cancelled... so having to Force Quit the App.
Going to re-install and see what happens
Ok, Uninstalled, removed preferences, "updated" from CC App
Still not working properly
Does your chosen location for the catalog backup have Read/Write permissions?
I've been backing up to the same place since 2013.
Nothing in my process has changed. Only software versions have changed...and I've not had any issues until these last two weeks.
Its a very large catalog, and has always been slow to backup... (usually a 5 min process). I've let it try for 15 with now... with no changes.
Last thing to try is letting it try and backup overnight...perhaps in the morning it will have completed it. (hopefully)
But if that turns out to be the case... Something is SERIOUSLY wrong that it takes significantly longer to back up.
A backup... regardless of my catalog size... needs to be able to happen before my battery backup dies (10 min)