File systems are a fragile part of any hard disk.  Crashes, hardware defects, and  power blackouts can lead to file system problems, including damaged file pointers or corrupt files. A corrupt file may also prevent programs from starting. TuneUp Disk Doctor, part of TuneUp Utilities 2012, solves this problem by thoroughly checking the following file system areas: 

• Disk sectors: All sectors containing data are checked and corrected if any  errors are found. If problems are found, TuneUp Disk Doctor tries to recover the data and marks defective sectors as “Bad”, which effectively prevents data from spreading to these areas in the future.  
• Free space: All sectors not containing data are checked and corrected, which may prevent the writing of files. 
• File and folder structure: Both file and folder content and structure are checked.
• Indexes: Corrupt file or folder pointers are checked and relinked if necessary. This helps in cases where files and folders are no longer visible in Windows Explorer.
• Security descriptors: Damaged NTFS security descriptors, which may allow unauthorised access or even prevent access to files and folders, are checked and corrected.