Q: Mouse cursor lags with external monitor

Yes, that is very likely..

Anyway I hope that Apple will fix this bug soon. I don't want to wait for Yosemite and hope that everything will be working flawlessly..

I have reported the issue to Apple using this page:

https://www.apple.com/feedback/macosx.html

Hopefully someone will take it seriously!

I have the exact same problem as you describe, two monitors connected.

"Solutions" so far

Tried every possible solution. I'm only able to make the mouse stop lagging/freezing by disconnecting and having only one active monitor (or mirror) but as soon as I go more than one (dual or more, extended display) the problem comes back.

So it's obviously has something to do with the graphics card or drivers. I'm very scared this might be a hardware problem.

Only temporary fix is to restart, but if you put it to sleep or change the display setup the problem will come back.

OS X or not?

10.9.4 did not fix this problem, just the same as it was in 10.9.3.

I don't know if this problem was on earlier OS X releases, since I just got these two monitors.I really hope this is software related...

Well, just experienced the mouse lag/freeze after a fresh restart. Had to restart again to make it go away.

Very frustrating!

Ok guys, this is really strange. I seem to have fixed the problem! (or at least mine)

This is my setup:

MBP Retina 13" - Late 2013

1x LG 24" (24MP76) bought 2 months ago

1x LG 24" (24MP76) bought a week ago, seems to have a newer firmware or revision

The HDMI->MiniDP cable was connected to the "older" display.

The HDMI->HDMI cable was connected to the new display.

By switching the HDMI->MiniDP cable to the "new" display, the problem disappeared. I'm unable to get the cursor lag again.

I've tried putting the computer to sleep, shut down the monitors, change display setup in System Preferences. Unable to get the cursor freeze/lag again!

Well, experiencing this too.

Setup:

OS X 10.9.4

Macbook Pro 15" Late 2013 with nVIDIA chip

miniDP to VGA adapter i just bought today

an LG W2452T as external monitor

I'm gonna test this with a Samsung and another Monitor by a dead brand i don't even know the name of anymore just to be sure it's not my monitor acting up. Although, i had it connected to a linux desktop some days ago.

have the same problem here.

OSX 10.9.4

Macbook Pro

Retina, 13-inch, Mid 2014

External monitors at the same time:

1. HDMI port to HDMI display

2. Thunderbolt port to thunderbolt-HDMI adapter to HDMI display

If only one display through HDMI port, everything works fine.

If only one display through thunderbolt-HDMI adapter, mouse lag.

Workaround for me, mouse lagging happens when I start my MBP every time,

after I change the Refresh Rate of the display connecting to thunderbolt (50Hertz to 60Hertz or 60Hertz to 50Hertz), the problem disappears.

(System Preference -> Display -> Refresh Rate)

I had the jumping cursor on my MacbookPro 8,2 with 10.9.5, so I upgraded to 10.10 public beta 3. It persisted. Long story short, for me it was f.lux, the app that tints the screen towards sunset to relax the eyes. Disabling it stops the jumping cursor! (Also, it only happened on my Dell U2412M at home, not on the Fujitsu P24W-6 I use at work.)

Does anyone else run f.lux?

Somebody suggested it might relate to newest Mavericks version, however I'm still on Mountain Lion (10.8.5) with a mid 2012 15' MBP  and recently started having the same issue. I'm using my MBP in clamshell mode with a Samsung SM24A550 external monitor and never had had any issue until about a month ago. At first I thought it was my old Mighty Mouse failing, but I replaced it with a Genius Bluetooth mouse and have the same problem with the freezing monitor/mouse. Maybe it's some update regarding firmware, otherwise I can't devise why it suddenly stopped working properly.

I do have the same problem. Reported twice, no response from Apple. I really hope it will be fixed as I bought the 13 inches for that purpose.

I've noticed another way to stop the lag (until the next time the monitor sleeps) -- unplug the mini display port connector and plug it back.

Can't believe this has been an issue for years...

I "solved" the problem by reducing the transparency from the System's Preferences on Yosemite 10.10 latest beta. I do have a MacBook Pro Retina Mid 2014 and do not understand why this kind of things can still hapen, even on a "GM". Thanks to Apple to solve it ASAP

I have a Macbook Pro Retina 15" mid-2012, connected to an Apple Thunderbolt Display, and I'm having the same issue with my Magic Mouse on the Yosemite GM. Huge lag, and unfortunately, disabling transparency in the Accessibility settings didn't help.

Ive had this same problem for the last 3 years on 2 different macbook Pros (17" early 2011 & latest mid 2014 MBP fully spec'd out) - and an apple thunderbolt monitor. The weird thing is that it just comes and goes from day to day. I can't find a pattern. It really *****. I bought the new mbp to fix the problem, but it didn't.

I have a late 2012 27" iMac with an Asus PB278Q external monitor connected via mini display port to display port. I have the the same cursor lag/eratic cursor issue with a bonus of both displays sometimes just being black. The cool part is that when both displays are black the cursor is visible and doesn't lag. Awesome. I bought several cable thinking that was the problem. The apple display always come back if I just unplug the cable from the mini port, and sometimes comes back if I turn the Asus off, although it can take a few tries. This is my work machine so this is very annoying. I had high hopes that Yosemite would solve the problem but it has not.

I'd also like to mention that this is my 3rd iMac, the other two have been replaced under apple care for excessive image retention. This one has it too but there is no fix and I can't afford to be without the machine while they're (not) fixing. Apple is really on a roll.