I know this is very old but i just had the same issue heavily on my Linux Mint System and in my case, it seemed to be a driver related problem so i also had to check for any updates:

sudo apt update && sudo apt upgrade

If it says any upgrades weren't concluded (due to phasing), check if they aren't causing the problem and execute them manually by typing:

sudo apt install 'upgrade-name'

After that, what i did was to press the Super key and type: "Startup Applications". Then search for the Blueman Applet setting and turn it off. Now, Reboot the system and enable bluetooth manually by pressing the Bluetooth icon on the System Settings (Control Center) menu under the hardware section.