Not sure where to post this.

Okay, when I turn my iMac on, the brightness is fine, really bright, the way I like it.
Over about 10 minutes later, the brightness suddenly goes down, however my "auto-adjust brightness' is turned off, definitely.

Some details :-
It's bright then goes darker, suddenly, overtime.
Auto Adjust is turned off, brightness is on full.

jakek140 said:

Okay, when I turn my iMac on, the brightness is fine, really bright, the way I like it.
Over about 10 minutes later, the brightness suddenly goes down, however my "auto-adjust brightness' is turned off, definitely.

Click to expand...

Hello and welcome to the forum!

Please provide information on your iMac (model/year) & OS X installed. First and if not already done, have you re-booted the computer; if so, any help?

Second, reset the SMC (System Management Controller) which might impact on the brightness adjustment - check HERE for further information and directions. Dave

P.S. Regardless of not being sure about which forum to use, your title should have been descriptive of your problem & issues - uninformative titles may be ignored - just saying.

Since the computer you're discussing is an iMac (a desktop computer)…the thread belongs best in the "Apple Desktop" sub-forum. Thread moved.

- Nick