I was helping another tech that was working on a Server in San Antonio. He was having a lot of trouble trying to get a Server using 2008 Standard R2 to backup to an external hard drive. At first we thought there was an issue with the drive so he took it back. Then, after installing the new 3TB drive we had the same issue. After doing some research we found that The limit Server 2008 R2 can backup to, or “see” is 1.5TB. So, if you are trying to get a server to backup and it keeps erroring out make sure that your hard drive is no larger than 1.5TB.