Your Mac system is not working properly because the catalog file is damage. This is quite a rare situation but if you are not careful enough the data loss due to it can be severe. The damage in the catalog file is mainly caused when the system abruptly shutdown or the Mac hard drive is infected by virus. It can also get corrupted when there is any interruption while the system is updating the catalog file. You can experience system freeze or even the Mac will not boot when the catalog file is damage. You can repair the catalog files by formatting the hard drive and reinstalling the Mac OS X. Now the new catalog files are overwritten on the previous corrupted file and you will not face catalog file is damage issue any time soon. You must wanting to recover the lost data for that you can use the backup or the Mac data recovery software. The software will scan the Mac hard drive for the erased data and show the scan results in the preview. Select the files you want to restore and the software will restore it back in the drive after you fix catalog file is damage issue.