A couple of approaches to see if Keynote subsequently behaves itself.
- Hold the shift key when launching Keynote after a crash and it will not attempt to load its last saved application state.
- Boot into Safe Boot mode by holding the shift key at power on until the progress bar appears. Try Keynote in this mode for awhile to see if it crashes, and then reboot normally.
If you are using any anti-virus tool, that can be interfering with both Keynote and the operating system. If this is the case, completely remove the anti-virus product.
If you are using a font manager, and have de-activated any fonts that Keynote requires, it will crash as often as it can until the font is re-activated.