Cannot copy windows to back-up hard drive

I have 2 hard drives. I can easily make duplicate copies of windows partitions on my master drive. But when I try to copy one onto my back-up drive I get the following message when I re-boot.

"Enter the name of the Command Interpreter (e.g. C\WINDOWS\COMMAND.COM)"

I then have to use the bootable Acronis Disk Director to clear/unallocate my back-up drive so that I can access the computer again.

To simplify it, I cannot copy windows from my master hard drive to my backup drive using the Disk Director. I know it works because I was able to do it once, and only once. I tried re-format and scandisk on my back-up to clear up anything that might be corrupted. Still no luck.

 

Found solution. Copied partition to back-up hard drive as a primary instead of logical. I could then boot both partitions. However they exchanged data.
If i put something on one partition it would automatically transfer to the other.

To fix this, I changed the partition on back-up drive to logical. Bingo, it worked. I can boot the drive and it doesn't exchange data.

Sounds logical to me, no pun intended.