I am having the same problem. I noticed it sometime last month. When I powered down the drive, then back up, both lights were solid. It wasn't until after I copied some files to it that the right side light started blinking. I have noticed also that the drive runs hotter with the light blinking and it sounds like a drive is still running, evening though I have the sleep timer set to 5 minutes. I have 2 1TB WD drives formatted as RAID 1, using firmware 1.07. They have been in use for right at a year now.