Bluetooth chip adapter missing in device manager.

There have been several reports about missing Bluetooth adapter from the device manager. This is not a case with Windows 10 alone. It can happen in several cases some of which can be listed out as

• After a clean installation of Windows.
• After installation of some scrupulous software.
• Installation of Windows updates.

The device may not be visible if the driver is outdated or the bluetooth service has not started. At times, the adapter may be listed under Network Adapters or Other Devices section.

Some of the options to sort out the issue - though I cannot assure you of the success - can be

• Disable Bluetooth service and then enable it again. Check if the adapter comes up in the list.
• Performing a System restore can solve the issue. Restore your system to a date and time when the service was working fine.

Another method that can work is

• Click on START and then Run.
• Type in Services.msc
• Right Click on Bluetooth Support service and choose Properties
• Select Start Up type as Automaticand then click Start under Service Status.
• Now click on OK

If everything fails, one of the good options would be use a USB Bluetooth adapter. As long as all other services are running perfect, the USB Bluetooth device should be able to work.
If all these methods fail, you may need to get your laptop checked.

The new Windows 10 by default makes use of the default generic drives for the Bluetooth and USB. So if those are not working then you have to look for the official laptop manufacturer website. You can also find the drivers based on the Bluetooth manufacturers website as well.

As your chipset is atheros - ar5bbu22. Most of thee driver download website has the download available for the official driver. You can download the driver from the following URL.

http://driverzone.com/%7B1a5f8cf8-2527-4af8-8024-81cd87b28593%7D?id=5149892

Or

https://drp.su/en/laptops/acer/aspire-5749?os=windows-7-x64

Choose the installer that allows one click installation of the driver file.

After downloading this driver. You have two following option.

1. Running the driver scan from the Windows device manager.
2. Installing the driver through the installer.

If you are running the driver scan from the Windows device manager,follow the steps below.

1. Go to Start menu.
2. Go to control panel.
3. Go to device manager.
4. Find the Missing driver icon of the Bluetooth in the dialog.
5. Right click and locate the menu that says search for driver.
6. Point to the folder where you have extracted the driver files.
7. Let the Windows 10 accepts the driver file.
8. Restart the machine.

Now after these steps you can confirm if the device has the Bluetooth service enabled by this driver.

Second option is to find the official installer of the driver. This helps you get the driver installed without you having to do anything. It also helps you to get the reboot message and validate the driver installation. I'd suggest going with that option and find the driver installer in above links.