No one wants to lose vital data stored on a hard disk. To ensure the integrity of data, backup copies can be the best line of defence. When the unthinkable happens, and data cannot be seen from the operating system, another route must be taken to retrieve lost data.
| Cause | Chance |
|---|---|
| Accidental removal of files and folders and then emptying Recycle Bin | ~ 75% |
| After physical damage of critical sectors on HDD ("bad clusters") some drives become unreadable | ~ 6% |
| Loss of information due to a power failure or power surge | ~ 5% |
| Deletion of logical drive or partition itself then recalling important data on it | ~ 3% |
| Damage of MBR, Partition Table, Volume Boot Sectors by virus | ~ 3% |
| Other | ~ 8% |
When the above cases are assessed, the situation boils down to two states:
