the action can't be completed because the folder or a file in it is open in another program

Hi Criggs. I've already posted this in the discussion somewhere.  But, so you don't have to sift through it, here is a workaround that releases the temp files preventing your action, but that doesn't require signing off or a reboot:

• In Task Manager, right click the Windows Explorer process and select "restart".

(if there are multiple instances, you might need to do the same for each... but usually one will do it)

• Explorer will disappear and reappear, and your folders will be unlocked…

You don't need to save everything... but do so perhaps the first time you try it, just to be sure.

Best

In addition to all the other solutions I've read about here and elsewhere (like changing caching of thumbnails in the Group Policy Editor, which is not available to Windows 8 Home users, and so forth and so on), I've discovered that one doesn't necessarily have to go all the way to restart, which many here and elsewhere have said is the only surefire way to fix this. 

Instead I found that if I simply sign off my computer and then sign back in, the folder/file is also unlocked and can be deleted.

Yes, that still means you have to save all your work before you sign off.  But it's still somewhat faster than a full restart. 

I'd like to know if others, faced with this problem, find the sign off/sign on option less burdensome than the restart option.  Thanks!

This may also be helpful:

Open Windows explorer.

Click ‘Organize -> Folder and search options’ (or ‘View -> Folder options’).

Select the ‘View’-tab.

In the ‘Advanced settings’ window, disable ‘Launch folder windows in a separate process’.

You may need to force restart all explorer instances (via task manager) or reboot your computer if the setting is not applied immediately.

What if it's already disabled and the problem persists?

That didn't work.  Has anybody solved this? Thanks.