第二台显示器提供了一种简单方便的方式来提高生产力或增强您的游戏体验。不仅如此，它还为您提供了一个更大的画布，作为一般多任务处理的额外工作区。
连接第二台 PC 显示器(Connecting your second PC monitor)通常是即插即用的过程，但在某些情况下，Windows 10 可能无法检测到显示器。此问题有几个基本的根本原因，例如电缆损坏或故障、您的 PC 缺乏对第二个显示器的支持、您的驱动程序已过时(outdated driver)，或者显示驱动程序无法处理第二个显示器。
如果未检测到您的第二台显示器，请使用本指南对您的显示器进行故障排除和解决问题(troubleshoot and resolve problems with your monitor)。
修复 Windows 10 中未检测到第二个监视器(Fix Second Monitor Is Not Detected in Windows 10)
您可以从以下基本故障排除提示开始。在您需要深入研究其他问题之前，这些可能会解决您未检测到第二台显示器的问题。
- 确认您使用正确的电缆(using the right cable)连接您的 PC 和第二台显示器。如果电缆损坏或出现故障，Windows将无法检测到第二台显示器。如果您更换电缆并且新电缆适用于您的显示器设置，则意味着旧电缆有故障。
- 断开(Disconnect)任何可能导致 PC 和第二台显示器之间发生硬件冲突的附件，例如已连接的适配器、加密狗或扩展坞
- 尝试将第二台 PC 显示器与不同的系统一起使用，以确定问题出在主系统还是显示器上。
- 检查第二台显示器是否连接到电源。一些显示器的背面有一个开关，用于打开显示器的电源。
- 确保(Make)使用显示器上的内置控件选择了正确的输入（HDMI、DVI等）。(DVI)
- 连接(Connect)另一台正常工作的显示器以检查问题是否与显卡有关。
- 您可能需要更新设置为第二台显示器的显示器的固件，以修复任何兼容性问题或错误。您可以通过访问显示器制造商的网站并查看支持页面以获取有关如何应用最新固件更新的信息来执行此操作。
重启你的电脑(Restart Your PC)
重新启动计算机可以有效解决许多问题，包括未检测到第二台显示器时。重新启动会关闭所有其他正在运行的进程，这可能会干扰您的 PC 和第二台显示器之间的连接。
要重新启动 PC，请单击Start > Power > Restart。
强制 Windows 10 检测第二个 PC 显示器(Force Windows 10 to Detect the Second PC Monitor)
如果您的 PC 和第二台显示器没有物理连接问题，您可以使用“设置”(Settings)应用程序强制检测第二台显示器。
- 打开Settings > System。
- 单击显示(Display)。
- 转到重新排列您的显示器(Rearrange your displays)部分，然后单击检测(Detect)。
连接无线显示器(Connect a Wireless Display)
如果您的物理连接（通过电缆）无法帮助 Windows 10 检测到第二台显示器，请尝试连接无线显示器。
- 打开Settings > Devices。
- 单击蓝牙和其他设备(Bluetooth & other devices)。
- 选择添加蓝牙和其他设备(Add Bluetooth & other devices)。
- 单击无线显示器或坞站(Wireless display or dock)。
确认无线显示器已打开且可发现。从列表中选择显示器，然后按照屏幕上的说明完成设置。
检查您的显示适配器(Check Your Display Adapter)
如果您能够连接一台外接显示器，但未检测到第二台显示器，则您的显卡（也称为显示适配器）可能无法同时支持多台显示器。在这种情况下，显示分离器(display splitter)也无法帮助您将显示扩展到第二台显示器，因为它复制了相同的信号，而不是创建两个独立的信号。
如果您的 PC 只有一个视频输出端口，则意味着您只能支持一台外接显示器。要支持多台显示器，您需要一个用于额外视频输出端口的USB适配器或一个扩展坞。
更新、重新安装或回滚图形驱动程序(Update, Reinstall, Or Roll Back The Graphics Driver)
有缺陷、过时或损坏的图形驱动程序可能是 Windows 10 无法检测到您的第二台 PC 显示器的主要原因之一。
要解决此问题，您可以更新、重新安装驱动程序或将驱动程序回滚到以前的版本，以修复和恢复计算机与第二台显示器之间的连接。
如何更新图形驱动程序
- 要更新图形驱动程序，请右键单击Start > Device Manager，然后单击显示适配器(Display adapters)类别将其展开。
- 右键单击您的显示适配器（显卡）并选择更新驱动程序(Update driver)。
- 单击自动搜索更新的驱动程序软件(Search automatically for updated driver software)，然后重新启动计算机。
如果Windows Update(Windows Update)找到更新的驱动程序，它将自动下载并安装更新。更新驱动后检查是否检测到第二台显示器。
重新安装图形驱动程序(Reinstall The Graphics Driver)
- 右键单击Start > Device Manager > Display adapters。右键单击计算机的显示适配器，然后单击卸载设备(Uninstall device)。
- 取消选中从该设备删除驱动程序软件(Delete the driver software from this device)框，然后单击卸载(Uninstall)。
- 重新启动您的 PC 并返回到设备管理器(Device Manager)。在Computer(Computer)下找到并右键单击您的 PC 名称。单击扫描硬件更改(Scan for hardware changes)。
在启动过程中，Windows会尝试自动重新安装显卡驱动程序，之后您可以尝试再次连接到第二台显示器。
回滚图形驱动程序(Roll Back The Graphics Driver)
驱动程序更新可以阻止Windows 10检测您的第二台显示器。如果发生这种情况，您可以回滚以前的图形驱动程序来解决问题。
- 右键单击Start > Device Manager，然后双击显示适配器(Display adapters)类别将其展开。右键单击计算机的显示适配器，然后单击属性(Properties)。
- 单击驱动程序(Driver)选项卡。
- 单击回滚驱动程序(Roll back driver)。如果回滚(Roll)驱动程序按钮不可用（灰显），则无法回滚驱动程序。但是，您应该能够从设备制造商的支持网站上找到旧版本的驱动程序。
如果回滚驱动程序按钮可用，请单击是(Yes)，然后重新启动计算机。
管理您的显示器 (Manage Your Displays )
如果您使用了上述任何修复程序，并且Windows现在能够检测到您的第二台显示器，请在评论部分告诉我们。有关双显示器设置的更多信息，请查看我们的指南，了解管理双显示器的最佳软件程序(best software programs to manage dual monitors)、如何将两台或多台计算机连接到一台显示器(how to connect two or more computers to one monitor)以及如何修复空白或黑色显示器问题(how to fix blank or black monitor problems)。
What To Do When Your Second Monitor Is Not Detected
Second monitors offer an easy and convenient way to improve productivity or enhance your gaming experience. Not only that, but it also gives you a larger canvas that actѕ as an additional wоrksрace for general multi-tasking.
Connecting your second PC monitor is usually a plug-and-play process, but in some instances Windows 10 may not be able to detect the monitor. There are a few basic root causes of this problem, such as a damaged or malfunctioning cable, your PC lacks support for the second display, you have an outdated driver, or the display drivers can’t handle the second display.
If your second monitor is not detected, use this guide to troubleshoot and resolve problems with your monitor.
Fix Second Monitor Is Not Detected in Windows 10
You can start with the following basic troubleshooting tips. These may resolve your issue with the second monitor not detected before you need to dig deeper into other issues.
- Confirm that you’re using the right cable to connect your PC and the second monitor. If the cable is damaged or malfunctioning, Windows won’t detect the second monitor. If you change the cable and the new cable works with your display setup, it means the old one is faulty.
- Disconnect any accessories like connected adapters, dongles, or docks that could cause hardware conflicts between your PC and second monitor
- Try using the second PC monitor with a different system to isolate whether the issue is with the primary system or the monitor.
- Check whether the second monitor is connected to a power source. Some monitors have a switch at the back to power on the display.
- Make sure the correct input (HDMI, DVI, etc) is selected using the built-in controls on your monitor.
- Connect another working monitor to check if the issue is with the graphics card.
- You may need to update the firmware of the display you’re setting up as a second monitor to fix any compatibility issues or bugs. You can do this by going to the display manufacturer’s website and check the support page for information on how to apply the latest firmware update.
Restart Your PC
Restarting your computer works effectively for many issues, including when your second monitor is not detected. A restart closes all other processes that are running and that may interfere with the connection between your PC and the second monitor.
To restart your PC, click Start > Power > Restart.
Force Windows 10 to Detect the Second PC Monitor
If there are no physical connection problems with your PC and second monitor, you can use the Settings app to force detection of the second display.
- Open Settings > System.
- Click Display.
- Go to the Rearrange your displays section and click Detect.
Connect a Wireless Display
If your physical connection (via cable) doesn’t help Windows 10 detect the second monitor, try connecting a wireless display instead.
- Open Settings > Devices.
- Click Bluetooth & other devices.
- Select Add Bluetooth & other devices.
- Click Wireless display or dock.
Confirm that the wireless display is on and discoverable. Select the display from the list, and then follow the on-screen instructions to complete the setup.
Check Your Display Adapter
If you’re able to connect one external monitor, but the second monitor is not detected, it’s possible that your graphics card (also called a display adapter) cannot support multiple monitors at the same time. In this case, a display splitter won’t help you extend your display to the second monitor either because it duplicates the same signal instead of creating two independent signals.
If your PC only has a single video output port, it means you can only support one external monitor. To support multiple monitors, you’ll need a USB adapter for an extra video output port, or a docking station.
Update, Reinstall, Or Roll Back The Graphics Driver
A buggy, outdated, or corrupted graphics driver may be one of the main reasons why Windows 10 won’t detect your second PC monitor.
To resolve this issue, you can update, reinstall, or roll back the driver to a previous version to fix and restore the connection between your computer and the second monitor.
How to Update a Graphics Driver
- To update the graphics driver, right-click Start > Device Manager and then click the Display adapters category to expand it.
- Right-click on your display adapter (graphics card) and select Update driver.
- Click Search automatically for updated driver software, and then restart your computer.
Windows Update will automatically download and install the update if it finds a newer driver. Check whether the second monitor is detected after updating the driver.
Reinstall The Graphics Driver
- Right-click Start > Device Manager > Display adapters. Right-click your computer’s display adapter and then click Uninstall device.
- Uncheck the Delete the driver software from this device box and then click Uninstall.
- Restart your PC and go back to the Device Manager. Find and right-click your PC’s name under Computer. Click Scan for hardware changes.
During startup, Windows will try to automatically reinstall the graphics driver, after which you can try to connect to the second monitor again.
Roll Back The Graphics Driver
A driver update can stop Windows 10 from detecting your second monitor. If this happens, you can roll back the previous graphics driver to fix the issue.
- Right-click Start > Device Manager and double-click the Display adapters category to expand it. Right-click your computer’s display adapter and click Properties.
- Click the Driver tab.
- Click Roll back driver. If the Roll back driver button is unavailable (grayed out), you cannot roll back the driver. However, you should be able to find an older version of the driver from your device manufacturer’s support website.
If the roll back driver button is available, click Yes and then restart your computer.
Manage Your Displays
If you used any of the fixes above, and Windows is now able to detect your second monitor, tell us about it in the comments section. For more on dual monitor setups, check out our guides on the best software programs to manage dual monitors, how to connect two or more computers to one monitor, and how to fix blank or black monitor problems.
