Catalog files are the crucial part of the Mac hard drive management as it contains all the information about the files that are saved in the drive. So when the Catalog File node corruption occur then the stored files will become inaccessible. The catalog files follows b-tree pattern where every node has specific data about certain file. The corruption can happen when the system gets abruptly shut down, there is any partitioning error, the drive is infected by any malicious program. You can use the inbuilt disk utility to fix Catalog File node corruption that is able to resolve some minor issues and if it is not fixed then format the Mac drive. This also erases all the files from the drive so you must be looking to recover it when the Catalog File node corruption is fixed. The time machine backup can restore the files from the copy it has saved in the external drive. But when the time machine is not working then you can use the Mac data recovery software to restore all your files. It will scan the drive to provide the preview where you can select the files for recovery. So download the software and use it now.