I finally jumped out of the pit after 8 hours, so I wrote this experience to warn future generations! ! !
Initially, the company was equipped with a set of DELL WM126 wireless mice; the picture looks like this:
By chance, I received a discarded receiver a few days ago that looked like this:
Usually the price of a mouse receiver accounts for more than half of the price of a set. I feel good. I want to try whether this receiver can still be used. I can start it as soon as I think of it. Of course, Dell products naturally require the use of a tool: Dell Peripheral Manager 157+ MB feels quite powerful. 
After the software is installed, it looks like this:
The software is almost the same, and the pairing is successful and smooth. However, when I finally switched to the built-in receiver, I couldn't connect it. The mouse was completely useless. I thought about using the pairing tool to re-pair it and give it a try! The result was an overturn
The wireless mouse and receiver cannot be connected. It prompts "The device has been paired. This device has been paired. If you want to pair again, please disassemble the device first." Such words mean that pairing is completely impossible and the pairing of the mouse device cannot be detected.
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I searched the entire official website and couldn't find the reason. The mouse was not responding even though it was paired. The user manual did not mention this prompt. I thought over and over again whether I needed to use an older version of the driver because the driver was too new, so I decided to go back to the official website. Found an older version of Dell Universal Receiver Control Panel called Dell Universal Receiver Control Panel:
After the installation is complete, you will get this:
I decisively removed the device and re-paired it. As expected, the code pairing was successful. I tried the mouse but it still doesn't work.
Try re-plugging and unplugging the receiver, restarting the mouse, and testing again. The results are pleasing to the eye.
It turns out that the new version of Dell Peripheral Manager tool cannot friendly identify the WM126 series single mouse receiver. Only the Dell Universal Receiver Control Panel coding tool released in 2015 can:
After successfully pairing the code according to the following prompts, don't forget to restart the mouse and unplug the receiver again and plug it back in.