Some apps won't work as I am running 2008 firmware on this TV. So I decided to try to upgrade it.
I have downloaded the firmware update from here https://www.samsung.com/uk/support/model/UE46ES8000UXXU/
I followed these instructions to the letter http://downloadcenter.samsung.com/content/FM/201303/20130306104951191/2012_TV_Firmware_Upgrade_Instr...
I made sure to format my USB drive as FAT32 and make sure my drive only contained a single folder containing the upgrade files, as recommended by others. The TV cannot find the firmware upgrade when I select upgrade by USB.
You did the right thing, so try with another USB execute the file, you select the USB via the browse button and the button extract in the last.
If the problem persists try a reset.