Q: iMac sometimes ignores left click

I had SmoothMouse installed (mirrors Windows mouse feel) and that was causing my issue. Hope it helps someone else!

Thanks for sharing, I've been plagued by this for almost a year, FINALLY FREE! I missed accurate clicks!

I've uninstalled SmoothMouse and the issue remains, unfortunately.

had similar issue after upgrading to El Capitan on MacBook Pro 13 Retina 2015, left click will not repond on the target point, but then clicking on some other area and clicking back on the target point will work, very irritating. Secondly, right clicking and clikcing the Get Info on files/folders will not work 1st time, but doing it again second time worked.

Fixed it these issues by doing a SMC reset.

Step1: Power off your Macbook Pro

Step2: Hold Shift+Control+Alt  +  Power for few seconds

There will be no indication but SMC will reset in the backend

Step3: Now power on your notebook normally by using the power button.

Issue should be fixed.

I'll suggest doing a SMC reset after every major upgrade.

Omg thank you, that's exactly the source of the problem I had !

In my case, I'm using a graphic tablet, and some fast drawings (while sketching) were missing.

I put the double click speed higher and TADA, fixed !

I am having similar issues on my MAC. I bought Macbook Pro 2015 15" retina display. Initially this was not an issue but it started slowly and has grown into a real problem. This problem not only exist in Safari but in all other apps as well. Left click just doesn't work until you click somewhere else and then click back on whatever you were clicking on.

I doesn't seems a problem which apple need million years to resolve rather with a small update or do they need to sleep on it to find some solution???

Apple please help...

You might want to consider starting a new discussion. Since this one is a couple of years old, less people are likely to look at it. You can link to this one.

Keyboard/Mouse – Troubleshooting Wireless

Reset an Apple Wireless Bluetooth Keyboard, Mouse or Trackpad (Troubleshooting Pairing and Other Common Problems)

Bluetooth devices become unresponsive

Bluetooth Interference Sources

Bluetooth Interference Sources (2)

Bluetooth Wireless Problems

If your Wi-Fi is capable of generating a 5 GHz signal, try that.

Restart the computer holding down the command - option/alt - P - R keys before the gray screen appears. Continue to hold until you hear the startup chime for the second time.

Reset NVRAM/PRAM

Holy cow! Changing double speed on fast also solved my problem and I have been trying to find the fix for 2 months. Thank you!