Time Machine is a very useful utility on Mac which provide backup in case of data loss and if there is any error you may have to repair Time Machine sparsebundle. Time automatically saves a copy of your file at regular interval in an external drive called Time Capsule. You have to set it up first and choose the preferred files you want to be stored as backup. You might be rest assured that all your files are safe but you can face a situation where you have lost some data and when you want to recover them by time machine it stars giving error. Then you will be left with no other option than to repair Time machine sparsebundle. It can be fixed by opening the utility folder and then access the airport utility. Now click th Time capsule and click Disks, disconnect all users and reset time machine preferences. You have to reconnect the Time capsule and click Backup now, if the backup starts then it is okay but if it fails then you have to use the Mac data recovery software to restore all the lost files. You can try to repair time machine sparsebundle afterwards but the recovery needs are solved by Mac data recovery software.