Can you give us some more information?
What version of Isadora are you using? (Go to Isadora > About Isadora and look at the splash screen. It will have a version number the four vertical dots to the right of "ISADORA".)What version of the Screen Capture plugin are you using? (Mouse over the plugin and the info panel in the bottom right, below the media view, should say the plugin version number after the name of the plugin.)Your operating system and hardware specs for the computer you're usingWhat you are screen capturing?Can you see it stutter in Isadora, or is it only stuttering on an external display? (If only on an external display, does your target frame rate from Isadora Preferences match the refresh rate of your external display?)Best wishes,
L Wilson-Spiro