Sorry - OS is win7 home premium - did not set a backup schedule. Went into backup settings - stated that last backup was 9/14 - but it showed that the backup was ongoing today. I went into backup on control panel - triggered a backup and then canceled. Msg now gone on action center. The WD external drive only backs up my personal docs - as I recall - so I guess I need to backup the windows OS portion of it as well. I may have indicated a monthly backup - I don't remember that action center message before this latest one regarding backup. will re-explore tomorrow. Thanks for input.  

Wanted to get back to you - I think what was bothering me was that the backup was going on for so long - as I said in my earlier msg,  I checked the settings, cancelled it and it stopped. I then set it to resume and it took about an hour to complete. Now at least I know what was going on - thanks for input.

That's good news. Another poster had the same problem and it turned out to be a bad hard drive that needed to be replaced under warranty. Keep an eye on it (even try another backup) and contact Support if it hangs again.

One last thought regarding this - I was having issues on random sudden frozen system (as I have posted elsewhere) - I ran all the diagnostics I could find in the Dell software package - all tests came out as passed. I am hoping those tests are accurate as the drive is included in many of them. Thanks again.