If you have a reasonably modern Mac and you have less than a handful of applications open, it’s unlikely your problem is due to lack of resources, since modern Macs come with quite a lot of memory and incredibly powerful CPUs. You have multiple applications all trying to use the disk at the same time.
The most common reasons for your Mac freezing / hanging and slowing down are: Typically, you’ll notice things start to slow down, the hard drive might become noisy, and you’ll keep seeing the “spinning wait cursor” (its official name, but commonly known as the “beach ball” or “wheel of death” - pictured above.) First, Why Does Your Mac Hang and Slow Down Anyway? Sometimes you’re using your Mac quite happily and suddenly things come grinding to a halt as an errant application begins to suck up resources and hangs or freezes your activities.
