Restore a complete Keynote presentation from Time Machine

The issue usually comes from how Keynote files are actually packaged. A .key file isn’t a single flat file; it’s a bundle with multiple internal components, so if Time Machine backed it up while it was open or mid-save, you can end up restoring a “complete file” that still only shows partial content (like one slide).

Instead of restoring the file blindly, go into Time Machine, navigate specifically to the folder containing the .key file, then keep stepping back until you find a version with a noticeably larger file size, that’s usually your intact version. Also, before restoring, right-click the .key file in Finder > “Show Package Contents” and check if the Data folder inside looks complete, if it’s missing assets, that backup is already broken. If all versions look wrong, your best fallback is Keynote’s built-in version history (File > Revert To), which sometimes preserves snapshots that Time Machine doesn’t catch properly.

Launch the Time Machine app or access it from the TM icon on the menu bar. In the TM interface, locate the file to restore. If the most recent version of the Keynote file is incomplete, then perhaps it backed up the damaged file you are trying to replace, so go back in time to access the next earlier version.

Restore items backed up with Time Machine on Mac - Apple Support

Here is another option for some apps:

View and restore past versions of documents on Mac - Apple Support

The late James Pond wrote an excellent illustrated guide to understanding and operating Time Machine and similar issues more than a decade ago. I have not seen anything that even comes close. This small section show details of how to restore, e.g., a folder:

Time Machine - Frequently Asked Questions

15. How do I view or restore selected items?

https://tommyang.github.io/pondini.org/TM/15.html