Unable to move folders in lightroom classic

I was regularly having the same problem and couldn't work it out. Today I went back to these files and looked at them in Finder. They were all locked files. I hadn't done this on the computer but I think it's possible that it may be remembering my lock info from the camera. When I got up the file info and unticked lock on each folder I was able to move them.

Fixed! Still don't why it all went pear shaped. Check all my permissions as suggested but they were fine. I store my images on 4 HDDs, internally. Each one has a master folder entitled My pictures1, 2, 3, etc. On the N drive the folder, which would have been My Pictures 4, was not displayed in the LR library. So, I went to the first dated folder in the LR library which is actually in the My Pictures 4 folder and removed one image, not delete from disc, just remove. Then I selected import, went to the My Pictures 4 library and selected that folder (it contains all the images in LR library under N:/My Pictures 4) As you'd expect all the images were greyed out as they are already imported, except thats is for the one I'd just removed. So clicked Import. That one file was imported into its original LR Library folder, or more correctly the link to that image. Now I can move folders back and forth between ALL drives 'til the cows come home. The question now remains, Why? Why would things change? and... why would my laptop behave the same. It is not synched or linked in any way to my PC and I only use LR on it occasionally for a quick edit or check  on something outwith my normal photo work. anyway, happy bunny again but thanks for your input folks.

1. Obvious question, Is drive N external? Is it connected?

2. is their an error message?

Have you tried resetting the Lightroom preference file as described in Method 1 in How to set Lightroom Classic CC preferences

Jao has you pointed in the right direction.

Moving files and folders in the Library module is still a simple drag and drop.

However, when moving folders or large number of files, it is better to do that outside of Lightroom as LR can sometimes drop the ball resulting in bad things.

That should still work just fine. Not sure what could cause it to not work normally.

You can always move the folder outside of Lightroom and then within Lightroom point Lightroom to the new location (the folder will get a missing icon on it that you can click or you can right click on the folder in Lightroom in its old location and select "update folder location"