Well, Leap 42.2 has been released two months ago, maybe try that?
Strange problem you have there though.
Normally Plasma5 should work, with the proprietary driver at least (nouveau does and did have its share of problems depending on the exact graphics card, that likely are more exposed by newer software like Plasma5).
Sorry, but I missed that thread so far.
Maybe something went wrong with the nvidia installation?
Should be fixable then.
I think that has fixed it. I selected ‘always’ trust for each repo, then rebooted. The autoupdate thingy ran and didn’t show the screen above.
It might also be a problem with that particular repo.
Maybe the repo’s signature has indeed changed again?
Personally I had that problem with some specific repos only, but since running “zypper ref” I haven’t encountered that again.
And that was two months ago or something like that.