Back Up Error Message

[LarryDavis5]

Using Acronis True Image for Western Digital - WD My Passport 2TB external drive - Win 8.1 - I keep getting the following error message when trying to back up my hard drive -
The IO operation at logical block address 0x6c08a8 for Disk 0 (PDO name: \Device\0000002a) was retried. Any idea what is causing this? And how to correct the problem?

 

[Kshipper]

Disk 0 could be your internal drive (and that is a worry). If it is..copy your data files right away and look into a new drive and a rebuild. If you have a good image that you can work from Acronis it looks like you will be using it shortly.