Mouse cursor lag on second screen

Question

Mouse cursor lag on second screen

Recently (since about the time I installed macOS Catalina Security Update 2021-004 10.15.7), at random times, the mouse cursor lags annoyingly when hovering over my second screen, but only over some windows, e.g. Mail, Pages, but not others, e.g. Safari, Finder. Happens whether that app is frontmost or not. No activity showing on Activity Monitor. Once the condition starts, it persists for a minute or so. Does not happen if the subject window moved to iMac screen.

iMac 2012, 27"

Catalina 10.15.7

Second screen connected via Display Port to DVI adapter.

iMac Line (2012 and Later)

Posted on Sep 26, 2021 3:19 PM

Reply

Answer 1

Jeff_W.

Community Specialist

Sep 27, 2021 2:30 PM in response to Gerry Pelletier

Hello Gerry Pelletier.

Thanks for reaching out to Apple Support Communities. We understand that the cursor for your iMac is lagging while connected to a second display. We will be glad to assist.

First, try an SMC reset to see if that helps:

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