Where is my software update file located?

A lot of my clients are asking this question.

When you are doing a software update from the  > Software Update menu, the package file will be stored inside your Mac HD/Library/Receipt. But this location stores only the application updates, not the security updates or the OS updates. Where are they?

This is a tricky one.

When you update the OS, the file will be temporarily stored inside your Mac HD/Library/Updates/xxxxxx-xxxx/

Those files will be gone as soon as you restart your Mac to complete the updates.

So, if you need to copy those file, be quick and do that before the OS asking you to restart your Mac to complete the update.