I have this issue on my Dell Inspiron 13 7000 series for very long time. I tried searching Google and Dell support community and I did:
Control Panel > Device Manager > Display Adapters > Intel HD Graphics 5500 > Driver > Update Driver > Search Automatically.
18:35 on 25-Dec-2016: Sorry bro, I did as above; it fixed but when I try pressing the brightness button then It come back problem again: can not adjust the brightness. Hic hic
19:00 on 25 Dec 2016: I even try downloading and installing the latest Intel Graphic Driver (issued on July 2016), but just after a while, the screen comes back very dim.
I accidentally discover this: Setting --> Display --> uncheck the box "Adjust my screen brightness automatically".
Sorry, but stupid Windows!!!!
Thanks, I had a similar problem (Latitude E6540, IPS display, stuck at brightest level) and reinstalling the driver in Device Manager solved the problem.
With regard to automatic brightness adjustment, I have also found that to be troublesome on a Windows laptop (HP, in my case). The display would slew from bright to dim or vice versa in a few seconds, for no apparent reason. It would be very frustrating to live with that for an extended period of time.
i have dell inspiron 15 3584 , the brightness is at maximum level and i cannot adjust my screen brightness...
this happens after windows 10 1903 update and it still occurs after windows 10 1909 update too...
please me in solving this problem...
I had the same issue and the suggestion to update the driver under Device Manager didn't work for me (it would simply say the driver was up-to-date). Installing Intel Graphics Command Center and adjusting the brightness from there worked (the brightness range goes from -60 to 100). Also, I would recommend to install Dell's SupportAssist because it found newer updates to the graphics driver that a simple Windows update missed.
I had a problem that my screen was very dark when on battery, ie not plugged in Despite exhaustive searching on microsoft, dell and throughout my computer, I was unable to find a slide bar that nearly every support blog says is there! Finally, after nearly a year of frustration, my IT contractor told me to do the following: immediately when powering on the computer, begin tapping the Fn F2 key. Continue this for about 5-10 seconds until the screen shows up with a brightness bar that you can then adjust. So simple, yet nowhere have I seen this posted.
Hope it helps others! (Inspiron 5000 series)