Magic Mouse lag issue.. new insight

Still no good. I can turn the router off and the problem will recur. I sold my 24" iMac and threw the Magic Mouse in thinking maybe it was part of the problem. Bought a new late 2014 mini and a new Magic Mouse. Same problem the first day out of the box. Thinking it may be interference somewhere in the house I took the mini to a cabin in the mountains with zero cell reception and no sources of interference. Plugged it in and within an hour the lag was as pronounced as ever. This is clearly Apple's issue and it has to do with the Bluetooth between the two devices - they designed and built both. There is no way people in their own campus and at all those Apple stores have not been fighting with this for as long as the rest of us.

The following two steps worked for me:

1. Change my wifi setting to use 5Ghz, as suggested in other posts. This worked partially, but not great.

2. What really fixed mouse responsiveness was turning off transparency in system preferences. In Accessibility > Display > check "Reduce Transparency".

Hi guys, for me works to repair the time machine disk, with this procedure my mouse is working pretty good!

I hope for somebody this works.

Thank you,

THAT's what really fixed my problem

I sometimes have difficulty with Wi-Fi or Bluetooth devices when USB 3 devices are attached to my computer. What could be wrong?

Some USB 3 devices, hard drives in particular, can generate radio frequency interference that can cause Wi-Fi and Bluetooth devices operating in the 2.4GHz band to have issues communicating with your computer. Do not place hard drives or other USB devices behind the rear of your Mac near at the hinge of your screen. The antennas for Wi-Fi and Bluetooth are located there, and USB 3 devices placed there may interfere with your wireless connections. See this white paper for more information.

Deleting the Bluetooth scripts and moving my portable hard drives from the vicinity of the iMac hinge did nothing for me...changing the AUTO channel selection of my wireless 2.4 GHz router did the trick.

I have a mid-2009 27" iMac running El Capitan.

This solution worked for me posted from another user...

SOLUTION (at least for one manifestation of this issue)

Mid 2010 MacBook Pro

BT Magic Mouse

BT Keyboard

I just started seeing lag on both devices today after them both working fine since I owned them, about 3 months. The lag I experienced on the mouse was like the cursor was being dragged through thick mud, completely unusable. For the keyboard is was delayed keystrokes.

For me, it was certainly and interference issue with my WiFi network (which my MacBook is also connected too). I determined what it was by

• finding this thread
• turning the WiFi (at the MacBook) on and off.

Sure enough, whenever the WiFi was off, KB and MM were back to full speed. What seemed to have triggered the issue was I moved the router closer to my MacBook (within one wall) and it was restarted when I moved it.

No amount of mouse cover removal, CMD-Option-P or re-pairing fixed the issue (I did see some brief intervals of them working, but nothing lasted).

I can't confirm for sure my WiFi router settings did not change after I restarted it but when the issue was prevalent my settings were:

Channel: Auto

Mode: 802.11n + 802.11g + 802.11b

Bandwith: 20Mhz/40Mhz

and to fix the lag problem immediately I changed the Channel to 1.

I've had problems with other devices (iPhone, iPad, Sony Laptop) in the past when I've fiddled with the settings but so far our other Apple Products (iPhone, iPad) are working just fine with the change.

Hope this helps someone out, this thread put me on the right track.

Message was edited by: mdsv