i had been using bluetooth fine, with devices working, but today when i turned on my computer again bluetooth strangely failed. there is a bluetooth icon on the top bar, showing "bluetooth on", but if i click on the "bluetooth settings" item, a system settings window shows up and shows me a bluetooth on-off switch which is disabled (i.e. fixed to off). more information about my case: i am a new linux used, coming from windows, and do not know supposedly-obvious commands. i am using a laptop. it initially doesn't have bluetooth. i bought a built-in type (instead of USB type) bluetooth module, and added it inside the laptop. hence, i do not have a specific FN+* key for bluetooth. in windows, i needed to install an additional driver that was intended for other machines in my laptop's seires which have built-in (i.e. factoryly built-in)j bluetooth modules. the Fn+* key seemed to only affect wifi under ubuntu. i have been successfully using magicmouse with my later-added built-in bluetooth module/adapter on both windows and ubuntu i have been trying to tweak the magicmouse scrolling speed with commands rmmod something, modprobe hid_magicmouse --scroll_speed=45 --scroll_acceleration=30 or something, then added a file `/etc/modprobe.d/magicmouse.conf". the mouse seemed to be working fine with these changes. now if i run commands like hcitool dev, the shell tells me that i do not have any "Devices" or "adapters". i seem to have bluez installed, because when i type "blue" then tab-autocomplete, a bunch of commands like bluez-test-device pops up. -- update -- some commands and their results: easoncxz@eason-Aspire-4741-ubuntu:/etc$ hcitool dev Devices: easoncxz@eason-Aspire-4741-ubuntu:/etc$ hcitool scan Device is not available: No such device easoncxz@eason-Aspire-4741-ubuntu:/etc$ rfkill list 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no 1: acer-wireless: Wireless LAN Soft blocked: no Hard blocked: no 2: acer-bluetooth: Bluetooth Soft blocked: no Hard blocked: no easoncxz@eason-Aspire-4741-ubuntu:/etc$ rfkill list 0: phy0: Wireless LAN Soft blocked: yes Hard blocked: no 1: acer-wireless: Wireless LAN Soft blocked: yes Hard blocked: no 2: acer-bluetooth: Bluetooth Soft blocked: yes Hard blocked: no