big slowdown on Mac os X big Sur. Case 1: Navigation in the finder Case 2: I click 2 or 3 times on the apple on the top left. In both cases, the rainbow wheel appears and turns for about 10 to 15 seconds. Mac end 2013 - 15 inches 2,3Ghz processor in qu'acore 16GB of Ram DDR3 App & System Services Core OS macOS 0 0 226 Dec ’20