My screen has a permanent floating window with an email address on

Try force closing all windows

Then boot to Safe mode and then to normal mode.

The as necessary

First try

Remove unwanted adware that displays pop-up ads and graphics on your Mac

Next:

Adwaremedic: Removes all known adware from your Mac

If you can't download it since the malware is preventing it then see:

https://discussions.apple.com/docs/DOC-7792

BaliWoodConcept wrote:

i have a permanent floating window showing an email address , want to erase.

Is this an e-mail address you recognize, or is it unfamiliar? Can you provide a screenshot of the floating window?

Make a screenshot by following the directions here:

http://support.apple.com/kb/HT5775

Be sure no sensitive personal information is displayed. To add that image to a post here, click the camera icon in the post editor toolbar.

Quit Mail if it's running.

I'm having the exact same issue. It seems to happen most often with Photoshop (CS 5.5), and it's a white box with the email address I most recently sent an email too. I feel, though I can't say for sure, that it happens most often when I've copied an email address, meaning the floating window has something to do with clipping or cache? Started when I updated to Yosemite. Apple Mail working with Gmail.

I'll try quiting mail, but I'd love a permanent solution.

Thanks