Error when running emulator: Not enough disk space to run AVD

The issue is not with the amount on your hard drive but the setting requesting how much storage space is required by the emulator.

In Android Studio, follow these steps to reduce the hard drive space requested by the emulator:

1. Click Tools -> AVD Manager
2. Click the edit icon for the emulator
3. Click the Show Advanced Settings
4. Under Memory and Storage, reduce the Internal Storage, specify something like 2048MB for an emulator that comes with Google Play store or less for emulators without the Google Play Store.

Try to run again and see if it works.

If the above doesn't work, try wiping out the user data from the emulator. You can wipe the user data from the actions sections on the AVD Manager screen.

It's not about RAM, if you are beginner just use the recomended amount of RAM when creating new AVD. In order to solve your particular problem, Go to the disc where is stored your AVD files, mine is in this Path:

E:\avd.android\avd\Nexus_5X_API_27_1.avd

and free up some space on that hard drive. Do not delete anything from avd folder ! If you do not know on which hard drive is stored your AVD files, go to Tools->AVD Manager

Choose your emulator and in it's drop-down list press the Show on Disc button. It will take you to that hard drive, then just free up some space. Not sure about minimum space, I have 20Gb and it works perfectly, you can start from minimum 5Gb. Also in that drop-down list try to Wipe the Data first and run the app, before trying to do all mentioned above.