Why is adb.exe not seeing BlueStacks?

Question

Android

Installed Bluestacks 2. The system also has Android Sudio along with the Android SDK.
For a while, adb.exe saw BlueStacks ("adb devices") and worked fine with it, but now it has stopped. The reasons are not known. What could be wrong?
PS: Happy New Year!

Answer 1

Alternatively, try just restarting Android studio. I've had this before, it always helps.