my emulator is not runnnig and gives the error in image below
and test at run window
C:\Users\Wahlah\AppData\Local\Android\sdk\tools\emulator.exe -netdelay gprs -netspeed full -avd Nexus_4_API_21 This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. terminate called after throwing an instance of 'std::logic_error' what(): basic_string::_S_construct null not valid
and second error exist is this image
I got the same problem with the same logged warnings and errors (and the alert as well).
Although from the first logged line (C:\...emulator.exe) it looked like the tools did find the emulator - my problem was resolved only after I followed this answer, and changed the ANDROID_SDK_ROOT environment variable (which pointed to a folder above the sdk instead to the sdk's folder itself).
So I changed it from
C:\Users\<username>\AppData\Local\Android
to
C:\Users\<username>\AppData\Local\Android\sdk
and... voila! The emulator is running properly.
I should note that I'm working on Windows and from the question it looks like AIR TRAVELS was as well.
I had the same problem and fixed it by selecting Cold Boot from the Tools > Android > AVD Manager > Edit > Show Advanced > Boot option from Quick Boot to Cold Boot. Hope this helps.
You can fix this error, need configure the device again. Download all the necessary libraries through the SDK manager.
来源：https://stackoverflow.com/questions/36521159/cannot-launch-avd-in-emulator-android-studio