I'm not sure what you ask for. It's just not possible. Windows does not allow it. You cannot "fix it". All you can do is to stop running WinSCP as Administrator (it's not a good idea in general to run applications as Administrator). Or do not drag from the Desktop. You can instead open the "desktop folder" in the local panel of WinSCP.

And how do I fix this?

You cannot drag from a process that does not run as Admin to a process that runs as Admin. That's Windows security restriction.

Yes, I'm running it as admin. Trying to drag&drop from desktop to FTP remote folder (and this doesn't work). Dropping doesn't work – it shows "not available icon" and just can drop anything to remote folder.

Did you try not to run WinSCP as Admin? Where exactly are you trying to drag from and where are you trying to drop to? What exactly does not work? Does dragging not even start? Or is it the dropping that does not work?

Hi,

just recently after installing new system I can't seem to make drag&drop feature working for some reason. This is the first time in years and I have no idea what might causing that :\

1. I'm running it as admin.
   
2. Tried changing options in "interface" preferences tab.
   
3. Tried changing drag&drop options in "interface" preferences tab.
   
4. I can drag&drop FROM server TO desktop, but not the other way.
   

Using Win10x64 Pro / 21H2. WinSCP 5.21.2.12723 If I can provide any other info please let me know.