I had a similar experience when I resumed working on my project on Android Studio after several months pause. I noticed that after upgrading to Android Studio Ladybug I could not start any of my virtual devices already setup in the Device Manager.

I tried many things, including deleting the devices, creating new ones, uninstalling Android Studio, reinstall SDK Tools, etc. but to no avail.

In my case I noticed that my graphics driver was updated recently. I am also using Windows 10.

I rolled back the driver to the previous version and now the emulator works again. The following is what I did:

• Right-click on Start menu and then select Device Manager
• In Device Manager select Display Adapters
• Select the graphics card for your system
• Open Properties
• Select Driver tab
• Click on Roll Back Driver

Not sure this is specific to my case as I have an older laptop, but perhaps you could give it a go if you think it could help?