Q: My trackpad and cursor are behaving eratically.

I'm using a iMac 27" (mid 2011)  with El Capitan 10.11.6.

My cursor moves erratically selecting all items in its path one ofter the other very swiftly, hence rendering the iMac unusable. This happens with the Apple Mouse / Track Pad / Keyboard, all Bluetooth.

The problem occurs intermittently (not every time the iMac is switched on). Is there any way / tool to identify the specific faulty part of the hardware? Have tried Troubleshooting with the Apple Telephone support and they feel it is a hardware issue.

I have tried a wired Keyboard (Windows) which seems to work fine.

I will appreciate any help / advise.

Suvransu Mitra

Kolkata, India