EFS - Back up encryption key – popup in Win7

Today I got a popup from the task tray on Windows 7 advising me to back up my EFS (Encrypting File System) certificate (key). This came out of nowhere and I haven't seen it but once before a long time ago, so I was a little concerned (that it might be a virus etc).

Here's some other folks who got the warning:
http://forums.dpreview.com/forums/readflat.asp?forum=1004&message=35959900&changemode=1
http://stackoverflow.com/questions/11699/efs-encryption-key-pop-up

Here's some info on how to tell if you have encrypted folders or files:
http://superuser.com/questions/37896/efs-find-out-whats-encrypted

I ran -      cipher /s:c:\ |findstr "^E"        -as administrator from the command line, and it didn't find anything.

Here's some info on how to turn EFS off:
http://www.vistax64.com/tutorials/102501-encryption-disable-enable.html