No preview in column view, in MacOS Mojave?

Hello.
I am experiencing some odd behavior on my two computers. The old one is an MacPro 5.1 with MacOS Mojave 10.14.6. The old horse wont cary a newer OS. In a finder window there are no preview? You focus on a file and the next column normally shows information about the file and a preview. No more after Christmas. The next column is blank.

The other odd thing is on my MacBookPro 16" from November 2019. There, I cant drag and drop a file, —sometimes. I find myself copying a file and move to the other folder and past it. This works. Also search for a “move the file” command in control-clicking the file. From a users point of view this is a fundamental brake in behavior we rely upon. I have wondered if this is about a file going out and in from iCloud?

Has any other a similar experience, or even found how to solve the brake in the user interface?

Fredrik

Take a look at the “Preview Options - items” dialog: Finder->View->Show View Options. If there are any items with enabled checkboxes, you should be seeing the Preview column. If any are enabled, I suspect your Finder.plist file is corrupt.

It was in the Show View Options.
This must have come with the last update. Thought I had checked all preferences, but obviously not.
Thank you!