Hi,
I had the same problem.
I run Windows back up to back up my exchange server 2010. it gives me the same consistency check failed and no logs were truncated. Tried so many things didn’t work.
I solved the problem by following below steps.
1. Make a full server back up even if it gives errors.
2. Enabling circular logging for the first data base.
3. Mount and dis mount the data base to apply circular logging option. (This will take minute or two depending on the size of your logs)
Now you will see all the logs belongs to that data base get deleted and big difference in the disk space.
4. Go back and Disable circular logging.
5. Mount and dis mount the data base to apply circular logging option
Do this to all the data bases and run Windows back, it will show successful.
Thanks,
Dilshan.