@carla_rogers,
On mac, Cmd + Shift + R is correct. If you open developer tools (Main menu --> More tools --> Dev tools OR Cmd + Shift + i) and right-click on the refresh button, you can see the options in the context menu – that way you know you’re doing the right thing.
I’m not entirely sure I understand your question – typically the data gets corrupted/stuck and clearing the browsers cache fixes that issue. But you are asking for examples where corrupted data breaks the cache clearing option? 