I can't delete or move screenshot thumbnails to trash on my iMac

Thanks. Forget about the "thumbnail" terminology for now... it was just confusing me.

sciencemagic wrote:

Hi John Galt,

You said, "Click anywhere on that Mac's Desktop background, then choose File > New Folder. An empty folder with title untitled folder should appear on the Desktop. Does it? When I open "new folder" a box appears for Finder? I then get the message "The operation can’t be completed because you don’t have the necessary permission."

That is not right. It means the Desktop permissions have changed for reasons unknown, which suggests other unknown changes may have affected that Mac.

The best way to describe how to change your Desktop folder permissions is to read Apple's Support document on the subject, here: Change permissions for files, folders, or disks on Mac - Apple Support

To change permissions for your Home Folder's Desktop folder, click anywhere on the Desktop background and then choose File > Get Info. The Get Info window should closely resemble the following:

Where it indicates "Read & Write" in the above example, yours is probably different. What does yours indicate?

• If it is not "Read & Write" you will not be able to alter anything on the Desktop.
• If "You can only read" appears under Sharing & Permissions, same problem. You won't be able to change anything.

To change the Desktop Permissions, follow Old Toad's instructions: click the padlock icon (lower right), authenticate with your usual login password, and change the dropdown menu to match the example indicated above. If it asks to "apply to enclosed items" say yes.

This may not be a permanent fix, or it might not work at all. Permissions don't get changed on their own, which is the reason I asked about that "HopToDesk" concern. If someone or some thing altered your Mac in an inept or malicious manner then greater concerns exist. If it works though, and everything else appears to work as it should, then I'd put the matter behind you.

Let us know what you determine.

Check the Desktop folder to make sure you have Read & Write permissions. Also that Admin has Read & Write permissions:

If you don't you'll have to unlock the padlock to change them.

Open a new Finder window and click on your Computer name in the sidebar. It will have a number of folders, one of which will be the Desktop. Control (right) - click on the Desktop folder and select Get Info from the Contextual menu. There you will find at the bottom the Permissions assigned to your Desktop folder.

 OT 

Is it possible the problems coincided with this event:

What is HopToDesk and do I need it? - Apple Community

Did you resolve that concern?

In a subsequent discussion you also described "thumbnails" appearing on the right side of your monitor:

Sort of weird situation I didn't have before when I could delete my screenshots thumbnails I had on the right side of my monitor.

Thumbnail screenshot issues - Apple Community

I'm not certain I understand the situation, because we don't generally use the term "thumbnails" to describe screenshots. That may be an unimportant difference of terminology, but describing their appearance as on the right side of the monitor is odd. Screenshots can certainly be deposited anywhere on the Desktop, and there are various ways of arranging Desktop icons, but I thought it odd to describe them in that manner. Are you describing Dock icons perhaps?

Anyway, to advance troubleshooting try this. Click anywhere on that Mac's Desktop background, then choose File > New Folder. An empty folder with title untitled folder should appear on the Desktop. Does it?

Drag that folder to the Trash. Any problems doing that?

Assuming you can do that, then your Desktop folder permissions are correct.

Write back with your observations and any other information that may help.

Where are you finding those screenshot thumbnails? Finder, or...?

By default a macOS screenshot is saved to the Desktop, its permissions will be the same as any other file in ~/Desktop and can be dragged to the Trash like any other. They are image files not usually referred to as "thumbnails" which is a term generally associated with apps other than Finder.

Take a screenshot on Mac - Apple Support

sciencemagic wrote:

Hi Od Toad,

I opened Finder and was able to access desktop from the options.

FYI your reply (above) did not appear for me until after posting mine. It's a recurring problem with this site. They're allegedly working on it.

Glad to hear the good news. 👍

 OT