Responsive design and unexpected error messages

No luck I'm afraid, I get the same error message as before when System - Slideshow CK is enabled.
Just to check, I downloaded the SlideshowCK.zip folder and installed it in the normal way.
The attached screenshot shows the current list of CK extensions, with the plugin disabled.
So far as I can see, everything else is working correctly.
Alan

ok, then I will need an admin and a FTP access so that I can investigate. Your situation seems strange because I do'nt see any reason why you would have this type of error
you can contact me by email to give me the access
www.joomlack.fr/en/contact

it's ok, the errors are now gone, with the plugin enabled
you can check on your side

I think that the problem is that the calendar triggers the event for the content prepare but the content object is empty
this fix in my plugin will be included in the next release

Excellent, and thank you for all your support. I've had a couple of weeks of annoying problems with my PC and the Joomla site. They're all unrelated, but I've been spending time trying to sort them out. One less thing to worry about now!

I don't know if it is relevant, but given the recent changes you made I thought I would start here.
A couple of days ago, I responded to a notification to update to Joomla! 4.4.6. Instead of the normal process and report back I got a screen I have not seen before ( see attachment)-Pre-Update Check for Joomla ‎4.4.6I wondered if it was a new feature but when I did a similar update to another site I manage, I found that behaved in the way I was used to.
I'm reluctant to proceed with the update until I know what is going on. 
Any ideas?
Best wishes,
Alan
 

Hi ex34mush,
sometimes when I read here in the forum and try to formulate a possible answer, I realize that it takes me 15 seconds to find something ready
I would like to be the one to write a good answer, but I find faster than I write.

You selected "Joomla Next" in the options update channel...!!!

Select System=1.40em → Update=1.40em → Joomla=1.40em → Options=1.40em → Update Channel

J4.x    
Pre-Update Check
from Joomla! Documentation
docs.joomla.org/J4.x:Pre-Update_Check


Greetings in all directions,
Heino