Brand: Dell
Category: Monitor
Document Type: Manual
Language: EN
Manual for U4025QW
Uploaded: Nov. 21, 2025, 6:47 p.m.
Warranty Information
Refer to the warranty information provided with your product or contact Dell for details on the warranty period.
About your monitor
The Dell UltraSharp U4025QW monitor features a 39.7-inch display with a 5120 x 2160 resolution and a 21:9 aspect ratio. It offers wide viewing angles with excellent color coverage (100% sRGB, 99% DCI-P3, etc.), tilt, swivel, and height adjustability, and integrated speakers. The monitor supports digital connectivity via DisplayPort, Thunderbolt 4, and HDMI, with Thunderbolt 4 ports providing up to 140W of power delivery. It also features a single-cable solution for network connectivity via an RJ45 port. The monitor includes Dell ComfortView Plus for reduced blue light emission and a flicker-free screen. It supports Picture-by-Picture (PBP) and Picture-in-Picture (PIP) modes and offers plug-and-play capability.
Setting up the monitor
Setup involves attaching the stand to the monitor by aligning the riser with the monitor and securing it with screws. The stand allows for adjustments in tilt, swivel, and vertical extension to achieve an ergonomic viewing position. Cable management features are also integrated to help organize cables.
Operating the monitor
The monitor can be powered on using the power button. Navigation and adjustments are primarily done using a joystick control and the on-screen display (OSD) menu. The OSD menu allows for configuration of various settings, including brightness, contrast, input source, and display modes. Features like Dell Power Button Sync (DPBS) and Menu Voice function are also available.
Troubleshooting and error codes
| Common Symptoms | What you experience | Possible solutions |
|---|---|---|
| No video/power LED off | No picture | Ensure that the video cable connecting the monitor and the computer is properly connected and secure. Verify that the power outlet is functioning properly. Ensure that the power button is pressed fully. |
| No video/power LED on | No picture or no brightness | Ensure that the correct input source is selected. Increase brightness and contrast controls using OSD. Perform monitor self-test. Check for bent or broken pins in the video cable connector. Run built-in diagnostics. |
| Missing pixels | LCD screen has spots | Cycle power on-off. A permanently off pixel is a natural defect. Refer to Dell Monitor Quality and Pixel Policy. |
| Stuck-on pixels | LCD screen has bright spots | Cycle power on-off. A permanently bright pixel is a natural defect. Refer to Dell Monitor Quality and Pixel Policy. |
| Brightness problems | Picture too dim or too bright | Reset the monitor to factory settings. Adjust brightness and contrast controls using OSD. |
| Safety-related issues | Visible signs of smoke or sparks | Do not perform any troubleshooting steps. Contact Dell immediately. |
| Intermittent problems | Monitor malfunctions on and off | Ensure proper cable connection. Reset to factory settings. Perform monitor self-test. |
| Missing color | Picture missing color | Perform monitor self-test. Ensure proper cable connection. Check for bent or broken pins in the video cable connector. |
| Wrong color | Picture color is not good | Change Preset Modes or Custom Color settings in the OSD. Change Input Color Format. Run built-in diagnostics. |
| Image retention from a static image | A faint shadow appears on the screen | Set the screen to turn off after idle time. Use a screensaver. |
| TBT out cannot display | The 2nd monitor cannot display, but the display setting recognizes 2 monitors | Ensure OSD Thunderbolt Daisy Chain is "Optimized". Check display settings. |
| The monitor cannot detect signal with dock after AC/DC Off/On, cable unplug/plug | No signal detected | Connect directly to the platform or change TBT4 to USB-C cable. |
| Two monitor maximum resolution cannot reach 5120 x 2160 @ 120 Hz when TBT Daisy Chain | Resolution limitations | Ensure OSD Thunderbolt Daisy Chain is "Optimized". |
| 2nd monitor shows black screen when TBT daisy chain and enable SmartHDR | Black screen on 2nd monitor | Intel UHD graphic limitation, suggest Intel Iris graphic. Disable SmartHDR. |
| Auto source cannot automatically switch to DP input source when DP cable is connected | No automatic source switching | Unplug and replug the DP cable. Manually select DP input source via OSD. |
| Screen image is too small | Image centered, does not fill viewing area | Check Aspect Ratio setting. Reset to factory settings. |
| Cannot adjust monitor with joystick | OSD does not appear | Turn monitor off/on, unplug/replug power. |
| No Input Signal when user controls are pressed | No picture, LED light is white | Check signal source, ensure computer is not in power-saving mode. Check cable connection. Reset computer or video player. Run built-in diagnostics. |
| Picture does not fill entire screen | Picture cannot fill height or width | Reset computer or video player. Consider video format aspect ratio. |
| No image when using DP connection | Blank screen | Verify DP standard, download latest graphics driver. |
| No image when using Thunderbolt 4 connection | Blank screen | Verify Thunderbolt 4 supports DP alternate mode. Verify device power requirement. Set Windows to Projection mode. Ensure Thunderbolt 4 cable is not damaged. |
| No charging when using Thunderbolt 4 connection | No charging | Verify device charging profiles. Verify Notebook power adapter requirement. Ensure Thunderbolt 4 cable is not damaged. |
| Intermittent charging when using Thunderbolt 4 connection | Intermittent charging | Check maximum power consumption. Use Dell approved adapter. Ensure Thunderbolt 4 cable is not damaged. |
| No network connection | Network dropped or intermittent | Do not toggle power button Off/On when network is connected. |
| LAN port is not functioning | OS setting or cable connection issue | Ensure latest BIOS/drivers. Check Ethernet controller installation. Ensure Ethernet cable is connected securely. Reconnect cable. Power cycle computer and monitor. |
| Detected light level drops significantly | Ambient light drops significantly | Check for obstructions or webcams over sensor. Clean sensor area. Ensure display is not pivoted. |
| USB interface is not working | USB peripherals are not working | Check display is ON. Reconnect upstream and downstream cables. Turn monitor off/on. Reboot computer. Connect high-power devices directly to computer. |
| SuperSpeed USB 3.2 Gen2 interface is slow | Peripherals working slowly or not at all | Check computer USB 3.0 capability. Ensure correct USB port is used. Reconnect upstream and downstream cables. Reboot computer. |
| Wireless USB peripherals stop working when USB 3.0 device is plugged in | Wireless USB peripherals responding slowly | Increase distance between USB 3.0 peripherals and receiver. Position receiver close to peripherals. Use USB-extender cable. |