Why my screen is flickering on iMac and Mac Air when I log on to Citrix for work? Does anyone have any suggestions? My Mac Air was updated about 3-4 weeks ago with Big Sur and then the issue came up. I thought my Mac book is old (about 10 years), so I bought a new iMac two weeks ago. The issue continues. But, Citrix works fine on PC. Please help me. The flickering drives me nuts when I stare at the screen for work.