To fix Input Signal Not Found on an HP monitor, wake the computer, select the matching input with the monitor's buttons and reconnect the video cable at both ends. If the message remains, work through the connection, display settings and hardware checks below.
The short version
- Wake the computer and check the monitor's power light.
- Match the selected input to the socket holding your video cable.
- Try another cable and connect directly without a dock or adapter.
- Use a working screen for Windows, Mac or Chromebook display settings.
- If the connection still fails, test the monitor and computer separately.
| Fix | What it does | Time | Use it when |
|---|---|---|---|
| Power and connections | Checks the signal route | A few minutes | Start here |
| Windows detection | Enables the external screen | A few minutes | Windows does not show it |
| Display modes | Corrects unsupported settings | A few minutes for settings | A display change caused it |
| Graphics drivers | Checks or restores drivers | A few minutes to check updates | An update caused it |
| Mac display checks | Redetects and approves displays | A few minutes | You use a Mac |
| Chromebook checks | Checks detection and USB-C | A few minutes | You use a Chromebook |
| Monitor settings | Resets controls and checks sleep | A few minutes | Inputs or controls misbehave |
| Cross-testing | Separates monitor and PC faults | A few minutes per connection | Earlier checks did not help |
Times estimate the checks with a spare cable or working screen ready. Downloads, recovery startup and restarts can take longer.
Check power and video connections
Wake the computer and check power
Move the mouse or press Space to wake the computer. If it stays asleep, briefly press and release the computer's Power button; check the computer's manual if its wake controls differ.
Turn on the monitor and check its power light, power cord and outlet. If the light stays off, reconnect the power plug at the monitor and at the wall outlet. Use a power cord and connection appropriate for your monitor, as specified in its documentation.
Match the input and check the cable
Look at the socket holding the video cable, then use the monitor's buttons to select its matching input. For example, a cable in HDMI 2 needs HDMI 2 selected. Use your model's manual to find its input controls rather than guessing which button opens them.
Turn off the computer before reconnecting the video cable, then secure both ends and turn it back on. If that does not help, try a known-working replacement cable. If the computer has another compatible video output, try that port too.
Bypass any dock, dongle or adapter and connect directly to the computer for this check. On a desktop with a separate graphics card, consult the computer's manual to identify the active video outputs and connect there. Their behavior depends on the graphics hardware and configuration.
If the HP screen remains unusable, use the laptop's built-in screen or temporarily connect a working monitor for the software steps. Follow the section for your computer's operating system, then return to monitor settings and cross-testing if needed.
Get Windows to detect the monitor
Press Windows + P and choose Duplicate to show the same picture on both screens, or Extend to spread the desktop across them. Choose Second screen only if you want the external screen alone. These choices apply to Windows 11 and Windows 10.
If the monitor is missing from settings, open Start > Settings > System > Display. Expand Multiple displays and select Detect. Use the working screen to make this change.
If the connection worked previously, press Windows + Ctrl + Shift + B to reset the graphics driver. If that fails, select Start > Power > Restart. Still missing the picture? Select Start > Power > Shut down, then turn the computer on again.
Correct the resolution and refresh rate
Choose supported display settings
Check display modes if the picture vanished immediately after a resolution or refresh-rate change. Using a working screen, open Start > Settings > System > Display and select the HP monitor. Under Display resolution, choose the option marked (Recommended).
On Windows 11, open Advanced display, select the affected display and choose a lower available value under Choose a refresh rate. On Windows 10, open Advanced display settings, select the monitor under Choose Display and change Refresh rate. The options depend on what the display supports.
Recover with low resolution startup
If startup appears but the picture disappears when Windows loads, try Enable low-resolution video. Have your BitLocker recovery key ready if the computer is encrypted. This startup option uses low resolution and refresh-rate settings so you can correct the display mode.
With a working Windows screen, hold Shift while selecting Power > Restart to enter Windows Recovery Environment. If no screen can show Windows, use Microsoft's recovery environment access steps to choose another entry method. Then select Troubleshoot > Advanced options > Startup Settings > Restart.
On the startup choices screen, press 3 or F3 for Enable low-resolution video. Once Windows opens, correct the resolution and refresh rate using the settings above. Restart afterward and check whether the picture returns.
Update or restore the Windows graphics driver
Check Windows and HP updates
On Windows 11, open Start > Settings > Windows Update > Check for updates and install the applicable updates. On Windows 10, the route is Start > Settings > Update & Security > Windows Update. Select Check for updates there.
If the computer is an HP PC, also check for a graphics-driver update for that computer model. Follow the steps for checking and installing HP updates to find the appropriate download. Choose the computer's graphics driver when troubleshooting its video output.
Roll back or reinstall the driver
If the failure began after a driver update, right-click Start, open Device Manager and expand Display adapters; the steps to update display adapters in Windows cover the same screen. Right-click the graphics adapter, choose Properties, open Driver and select Roll Back Driver. You need administrator permissions; follow the prompts and restart if requested.
If rollback is unavailable or does not help, save your work and close your apps. In Device Manager > Display adapters, right-click the affected adapter and choose Uninstall device, then confirm with Uninstall. Restart the computer so Windows can attempt to reinstall its driver.
If the driver does not reinstall, return to the adapter in Device Manager, right-click it and choose Update driver. Select Search automatically for drivers and follow the prompts. A separate monitor driver is mainly worth checking when display modes are missing; the FAQ explains that download.
Reconnect and detect the display on a Mac
Disconnect the display from both the Mac and its power source, then reconnect it. Check that the cable and any adapter support the display's resolution and refresh rate. Also check your Mac model's external-display limits, especially if other screens are connected.
On macOS Ventura 13 or later, open Apple menu > System Settings > Displays. On macOS Monterey 12 and earlier, use Apple menu > System Preferences > Displays. Hold Option to reveal Detect Displays, then click it.
On a Mac laptop with Apple silicon running macOS Ventura 13 or later, unlock your Mac, reconnect the accessory and choose Allow if prompted. These versions ask you to approve new or unknown accessories by default. For use with the lid closed, connect the Mac to power and use an external keyboard and mouse.
If the picture disappeared after changing the Mac's resolution, wait 15 seconds for it to revert. If it does not, press Esc to restore the previous resolution.
Check the display connection on a Chromebook
Select the time, then Settings > Device > Displays. Choose Mirror Built-in Display if you want the same picture on both screens. That option appears when the monitor is connected.
To adjust the external screen, select the monitor's name rather than Built-in Display. Check its Resolution and refresh-rate options there. If the monitor is not detected, return to the input and cable checks before changing display settings.
If you see Cable may not support displays, replace the USB-C cable with one rated SuperSpeed USB 5 Gbps or higher. Check for the certified logo on the replacement cable or its packaging. A cable that cannot support this connection needs replacing even if its connectors fit.
Restore the monitor settings and check sleep controls
Use the monitor's buttons to open its on-screen menu and select Factory Reset, as documented for your model. Afterward, check the selected input again. Consult the model's manual if the command or button layout differs.
On the HP 534pm, open the on-screen menu and choose Input > Auto-Switch Input > Off, then select the connected input manually. Use these controls only on models whose manuals document them.
These button-lockout operations require the monitor to be on, displaying an active signal, with the on-screen menu closed. If the HP 534pm shows OSD Lockout, hold its Left button for 10 seconds. For Power Button Lockout, hold Power for 10 seconds.
For sleep-related trouble, use only the controls your monitor's manual documents. On the OMEN by HP 25 Display, press the rear Menu button and choose Power Control > Auto-Sleep Mode > Off. This changes the monitor's sleep behavior; the computer still needs to send an active video signal.
Test the monitor and computer separately
Connect the HP monitor to another computer that has working video, using a known-working cable. Then try a working monitor on the original computer. Keep track of which combination produces a picture so you can identify where to seek help.
If the HP monitor works on the second computer, focus further checks on the original computer and its connections. Use the working monitor to finish the driver checks. If several working monitors fail on an HP PC, ask HP for computer diagnostics and support.
If the HP monitor remains blank on another working computer with a different cable, contact HP for service. A warning message shows that the monitor can display that message, so keep checking the incoming video signal. That observation alone does not rule out every monitor fault.
Frequently Asked Questions
How do I install an HP monitor driver when display modes are missing?
Open HP Software and Driver Downloads, select your product type and find your monitor model. Follow the prompts to choose and download the software available for that model. Follow the package's installation instructions, checking its system requirements before installing it.
Why does my HP monitor lose its signal only when the computer is idle?
Check the computer's screen-off and sleep timers. In Windows 11, open Start > Settings > System > Power & battery > Screen, sleep, & hibernate timeouts. Adjust Turn my screen off after and Make my device sleep after; on Windows 10, find the screen and sleep timers under Settings > System > Power & sleep.
Does every USB-C port support a monitor?
No, check the computer's port specifications before using it for video. An HP monitor connection that uses DisplayPort Alt Mode needs a computer port that supports that mode. A matching connector alone does not confirm that support.
What should I do if my work Mac will not let me approve the display accessory?
Ask your administrator to review the accessory approval setting. On supervised Mac laptops with Apple silicon running macOS Ventura 13 or later, administrators can manage it through Apple Configurator. Ask them to check whether your connection is allowed.
Does Input Signal Not Found mean the monitor is broken?
The message points to a missing video signal rather than proving that the monitor is broken. Check sleep, input and cables before testing it on another computer.
Do I need a separate HP monitor driver for normal use?
A compatible Plug-and-Play connection can work without installing a separate monitor INF file. If display modes are missing, check the monitor's downloads and the computer's graphics driver before seeking hardware support.