I'm unable to "safely disconnect" My Passport after running successful backup

I’m unable to “safely disconnect” My Passport 1 Tb USB HDD from my PC after completing a successful backup. I get a message that a program is still using it though I’ve stopped the backup. I’ve tried the method listed here http://support.wdc.com/KnowledgeBase/answer.aspx?ID=5316, and I’ve made sure the partitioning is turned off on My Passport. What program is still using the My Passport and how do I stop it so I can safely disconnect My Passport?

Hello,

Sometimes this happens on Windows computers. I recommend you shut down the computer and disconnect the drive while the computer is off.

Thanks for the suggestion. I found another suggestion to shut down my PC and restart it, then try to disconnect using the WD software, and that worked. For some reason by shutting down my computer and restarting it the WD disc drive no longer thought it was being used by another program.