今天打开笔记本，发现ikbc的dc87键盘的蓝牙怎么也连不上，尝试了在蓝牙设置和设备管理器里删除该设备，后再重新配对，然而无法解决。

sigh… 好吧，决定开始排查问题：

1. 键盘恢复出厂设置，重新请求配对时，win10里的设备列表里已经显示有配对的键盘：HM_KBx
2. airpods能连上电脑，排除了笔记本蓝牙硬件问题
3. 键盘能连上手机，排除了键盘蓝牙硬件问题

至此，可以判断出是win10系统的问题。问题比较奇葩，我的推断是在win10里没法彻底删除蓝牙设备，其中的现象是我在蓝牙设置删除了HM_KBx后，随后隔几秒钟HM_KBx又出现在列表中，显示的是已配对。

然后找到了这篇救命文章： How to completely remove a Bluetooth device from Win 10?
里面的人也是类似问题，跟着下面的Solution执行一遍，把所有已配对的设备删除之后，再重新配对键盘，fixed！

wouldn’t normally necro a thread but i spent two weeks trawling the
internet trying to sort this out and this thread is pretty high up on
the search rankings, hopefully can help someone.

My symptoms:

• Previously working bluetooth speaker (UE BOOM 2 in my case) stops connecting
• Windows 10 ‘Bluetooth and other devices’ menu shows the device as Paired
• Pressing connect makes it attempt to connect but fails then it goes back to Paired
• Remove device hides the device from the menu, but as soon as you turn bluetooth on and off, or restart the computer, the device comes
  back
• You pull your hair out.

Solution that worked for me after much, much unsuccessful internet
trawling and one system restore:

• Download this 7 year old command line bluetooth toolset: Bluetooth command line tools - work with bluetooth from the command line
• Install it, make sure you enable the option to “Add Bluetooth Command Line Tools directory to path”
• Open Powershell
• Put your device that isn’t working properly into pairing mode WARNING: THE FOLLOWING COMMAND WILL UNPAIR ALL BLUETOOTH DEVICES
• type in “btpair -u”
• Boom, all of a sudden Windows asks me if I want to allow pairing to my device that isn’t working
• Hit yes, successfully connected again
• Cry tears of joy

God I hope that helps someone else.