Is Your Mac “Beachballing” A Lot?

More than likely there’s a small bit of disk damage.

Re-boot in Single User Mode: Restart and while it’s restarting hold down the the Command + S buttons. It’ll pull up a Unix command prompt type screen. At the prompt type : fsck -fy
Remember to put that space after the k.
This will do a disk check like windows does a lot automatically.
If it does find something it will automatically fix it, but if it does find something, re-do the whole process over again because sometimes when it finds something, that will allow it to find something else. So, if it finds and fixes something, keep running the process until it says everything is fine

(Credit MacBreak Weekly Episode 81, Merlin Mann & Andy Ihnatko)