Very strange. Never seen anything like that
When you delete to recycle bin. All MC is doing is to send the list of files to be delete to windows. and Then Windows goes and moves files to recyle bin. if it is very fyll. WIndows will start to actually delete files from the bin..
Looks like something is block MC from deleting. And So MC is waiting for the delete to finished but something is blocking it.
Are you copying to/from some special device . or is everything from and to normal local HD ?
And since the dialog is blank it does not even start..
Something is really weird. something is halting MC from continue when it want to copy/delete.
Only normal reason is security software. But you say don't have that. So than I don't know.
You can try to create a dump of MultiCommander when it is hanged and then upload it to
http://multicommander.com/upload (pack it first)
Then I might be able to see what MC is waiting for. (Create dump from task mananagers detail tab. Right click on "multicommander.exe" and select "create dump file"