Can't paste anything into illustrator: always get empty "x" box.

This has been happening since last week. Anytime I try to copy and past an object (simple or complex), Illustrator assumes a bug. I get a "object" box with an x, I can't do anything with, nor resize or recolor. The name of the object automatically sets to "path" or an infinity of leters and numbers if it happens to be an object like a linked photo. Tried the Manual Copy and Paste with the mouse and it doesn't work either.

Shift + Alt DRAG still work to duplicate objects, which is the reason this bug is driving me insane. My workflow is completely ruined, so I'd really like to get a fix on this. 

Working on a Windows machine, fully updated and with all adobe software updated as well.

In the linked image, there's the butterfly I SHIFT + ALT DRAGed to duplicate, and in the middle, the error i got from pasting.