Hi - bear with me. I'm a Windows man but the wife has a iMac.
Her iMac is one of the ones affected by the duff HD. Therefore before I take it in for a replacement HD I have to back everything up. I do have Time Machine active, but I assume that won't work once a different HD has been installed. I thought I could use iCloud for back-up but in spite of having it active on the Mac since it it came out no backup has taken place ( yes all the boxes are ticked on iCloud set up).
Have I got the wrong end of the stick and iCloud is there just to sychronise all your Apple products and not for back-up purposes?