Here's another thing that was driving me nuts. I use an encrypted folder on my portable computer for my sensitive data, just in case it gets stolen. I always had a load of trouble trying to copy things back from the portable to my main computer (on which I do not use encryption.) Whenever I tried to copy or xcopy a file, I got the following error:

The specified file could not be encrypted.

But I don't WANT to encrypt it! Just copy it, you moronic computer!

Finally this morning, I found the right Microsoft page that shows the copy/xcopy options that I need to enable copying to a non-encrypted destination:

copy /d
xcopy /g

At last!