I already gave up of using my iPhone as Internet connection by Bluetooth PAN because if I close the Macbook, or it sleeps, after re-opening the connection is gone, and will not come back. But I have a good mouse: Microsoft sculpt touch mouse. It lost too, I have to pick a wired mouse or restart the Macbook.
This mouse already has the random lost of connection when Macbook is awake but it always reconnect (I am aware this is a common problem with bluetooth mouses, at list with El Capitan). As the PAN connection, bluetooth is lost almost every time I close the Macbook or after sleeping. Sometimes, the mouse come back after a while (minutes later) – mysterious!
I have researched around the web about, there was a solution for Yosemite by command line to restart the service, but won't work on Capitan. I could kill the Bluetooth but could not restart it.
Yosemite solution in githubgist
I found a complex solution that needs home-brew and blue tools installation, will monitor the wake up and restart the bluetooth service automatically (If I understood right). But is not an end user solution, imo.
Is there any simpler solution?
EDIT: Sometimes the mouse is back when Mac sleep and awake again. One thing was working: move the mouse to wake it BEFORE opening the Macbook. Always worked. I did reset all Bluetooth and delete the .plist file – observing the behavior…
I have come across many cases of various Microsoft Bluetooth mouse users having issues, so as a minimum some of their Bluetooth mouse products appear to be very fussy.
However, one thing I have seen that does work in some cases is to make sure it's the first Bluetooth device paired to your computer.
In a nutshell you need to reset both the macOS Bluetooth Device List and Bluetooth Controller. However, this will reset all connected Bluetooth devices, including a keyboard and mouse.
In other words, this will remove all existing pairing information for Bluetooth devices, so each will need to be reconnected. I have some steps you can follow, but I strongly suggest you read all of the steps first before commencing (or perhaps print out the instructions / view them on another device).
Before starting, ensure you have the Bluetooth icon showing in the menu bar. If it is not there, open System Preferences > Bluetooth and enable the option Show Bluetooth in Menu Bar.
Also, since you're trying to resolve an issue with a Bluetooth mouse, you will need to use another mouse to follow these steps:
Let me know how you go.