I wasn't sure where to post this. In my home office, I have a 2019 27" iMac (for home use) and an HP EliteBook Windows 10 laptop (for work). I keep a Samsung UE510 UHD monitor attached to the HP laptop via a DisplayPort cable. For the past three years, it's been working fine at 4K resolution. I recently got a new desk, so I had to disassemble and reassemble my setup. When I reattached the monitor, my laptop didn't recognize it. After I unattached and reattached the cable and powered the monitor off and on a few times, the laptop finally recognized it, but everything looked a bit fuzzy. I checked the settings in Windows, and the resolution is at 2560 x 1440. 3840 x 2160 is no longer an option, but 2560 x 1440 and everything below is. So I attached the monitor to my iMac using a Thunderbolt-to-DisplayPort cable. It has the same problem: macOS 12 thinks that 2560 x 1440 is as high as it will go. Two different computers and two different cables would seem to indicate that the problem lies with the monitor, but I've never heard of monitor no longer working at its native resolution but working fine at every resolution below. A Google search revealed no other instances of anyone else with this problem, and the Samsung support site says that a Windows 10 driver update in February caused this problem, but they subsequently fixed the bug. Any ideas?
