mac os catalina corrupted how to reinstall

You can also use the 10.15.2 Combo Update to overwrite any system software that is corrupt:

Download macOS Catalina 10.15.2 Combo Update

The Combo Update is a fuller install, as opposed to an incremental "delta" update, so it should overwrite any files that are damaged or missing. It does not matter if you have applied it before. It should preserve all your data and settings but that said you should always have a backup.

You might want to explain why you think Catalina is corrupt.

You can do a complete reinstall if needed.

How to reinstall macOS from macOS Recovery - Apple Support

Well yes, that will do it. Boot into Recovery Mode Command-Option-r keys and choose Reinstall Mac OS:

How to reinstall macOS from macOS Recovery - Apple Support

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