There has been so much development on our Xperia c and one of the important ones is the CLOCKWORKMOD RECOVERY.
It is very useful in making nandroid bacjups and restoring them when required
This is also for those who feel that md5 checking takes lots of time.Follow this tutorial to disable the md5 check.
It happened to me also and after a little tries I was able to sort it out.
I am sharing to help other fellow users of this device.
Here is the process..
1-)Go to sdcard/clockworkmod/backup/[your backup name]/here
2-)Copy the nandroid.md5 file and keep it somewhere safe.
3-)Open the nandroid.md5 in the backup folder file with any text editor and DELETE all the inside contents.
4-)Now save the file and try restoring your backup again.
5-)This will OVERIDE the md5 checks and the restore will begin.
All done enjoy nandroiding...LOL..
Press the thanks button if i was able to help you...