Acronis true image 2014 nonstop backup heavy disk IO

A problem I have with all three of my installations, two on Windows 7 pro, the other on Windows 8.1 is very heavy disk IO on the system drive. In a 12 hour period I can have as much as 1TB of read/write data on my "C" drive. It appears to just read data and then write it back to the drive. There is no increase in space used, just reading and then writing .

When I look at how things are being read and written the queue length is very close to being the same for read and write, the number of files being read and written are the same, or very close. As I said at the end of a 12 hour session (up time) the drive has written and read 1TB of data.

Has anyone else had the same problem and if so do you have a fix. I have turned off NSB and gone over to a backup every hour. Oh insistently It doesn't matter whether I pick the whole drive or one folder the symptoms are the same.

Rob