Text input not working in build on Mac OSX 10.8.5

Hello All. I have a encountered a weird issue here. We created a Mac Build which runs fine on all versions of Mac except Mac OSX 10.8.5 .

The issue is - When we run the build and try to login into the build, we are not able to type anything in the text field. Though I can see the cursor in the textfield when I click on it.

I checked to see if my keyboard is working. I also checked to see if any input settings have gone wrong but everything seems to be fine.

So my question is -- Is this a unity issue? Or an issue with the way this particular MAC OS is handling my unity build.? Or is there some particular setting that I must do so that the build works fine.?

Thanks for your help in advance.

Regards.

Harmit.