AC Adapter Unknown Device Installed – What is It?

AC Adapter: Unknown Device Installed is a warning message in the BIOS of a laptop which indicates problem regarding the AC Adapter. We will discuss the reasons for this warning, and because this is a device related issue, we will tackle several options that you may consider to solve this problem.


There are several reasons for the warning “AC Adapter = Unknown Device Installed” in your BIOS, one of which is due to outdated or corrupted device driver that can be solved using a Sophisticated Driver Software. In case that you’re experiencing AC Adapter issues, you can try to run a free scan of Driver Detective today and check if it will detect the cause of your Unknown Device problem. If the Free Scan Result lists your AC adapter device as one of the problematic devices with missing drivers, your problem may be solved in a few easy steps by letting Driver Detective guide you through the process of searching and downloading your AC Adapter’s device driver.

Other very common reasons of this “AC Adapter: unknown device installed” may be related to:

1. Faulty Power Cord
2. Faulty Power Plug
3. Faulty DC Power Jack
4. Defective AC Adapter
5. Defective Battery

Before purchasing any replacements, you should try to troubleshoot the problem to figure out which of the above issues might be troubling your PC.

Here are some suggestions worth considering:

If you are able to, try to borrow an AC Adapter or battery first and try them on your laptop before purchasing new ones, to see whether one of these two is causing AC Adapter: Unknown Device installed problem.

First and foremost, very carefully visually examine the power cord of your AC Adapter. Watch for any bare wire areas, you don’t want to get electrocuted! After you are certain that the power cord is fully isolated, try wiggling the cords of your AC Adapter, or gently tighten the connection of the plug and the power jack. You can also try to reattach the plug a little bit, but make sure that it’s still connected to the power jack. You can also tighten the cords by rolling or pinching them, and then check if the AC Adapter will already function or you still see the warning AC Adapter Unknown Device Installed.

These approaches may do the trick for a short period of time, but eventually you may have to buy a new AC adapter, replace the power cord, or DC power jack. For some of these you would definitely need to consult a PC technician.

We hope some of these suggestions will help you solve your computer’s “AC Adapter: Unknown Device Installed” problem.