It will be long, so it may not be an answer, but I will fill in the answer column.

Changed the Windows user name from "Change account settings".

If that is the case, there is no problem. However, it will not be a solution. The operation only changes the appearance of the user name displayed when logging in, the name of the folder itself is not changed.

By default, the files related to the Android emulator areC:\Users\\.android\It will be expanded in a folder called. I'm confirming that the emulator does not work properly ifcontains Japanese characters. Although it has been improved in the past, it seems to have come back.

By environment variable.androidIt is possible to change the location where the folder is created, but it seems that some files will remain in an inconvenient place even if I do it, and I have not tried it alone to improve it. did. (If anyone can improve this way, I would love to hear from you.)

Therefore, at the moment, I think there is no choice but to run the emulator in an environment wheredoes not contain Japanese. However, as I mentioned earlier, "Changing account settings" should not have been done until you rename the. Please note that the "visible folder name in Explorer" and the "actual folder name" may differ in Windows.

So, I'm sure that I'll be sure to create a new user consisting of only alphabets as a local account, log in with that account, start Android Studio, and run the emulator.

Open Settings (not the control panel), select "Accounts" ->"Family and other users", select "Add other users to this PC" on the other user's side, and set the Microsoft account in the popup window. When the screen appears, select "I do not have the sign-in information for this user", select "Add a user who does not have a Microsoft account" on the next screen, and give a non-Japanese name to the next screen Then, if you set a proper password and complete it, you can create a local account. When complete, log in as this user.

I don't know where you installed Android Studio itself,Program FilesYou can also start it from another user if it is under. When you start Android Studio for the first time with another user, the first time setup wizard will start, but in that, the screen asking for Install Type will appear as shown below. Select Custom here.
Install Type

After that, some screens will be the screen of SDK Components Setup, but at this time, click the folder icon on the right side of Android SDK Location at the bottom, and from the dialogC:\Android SDKChoose. Then, a message such as "An existing Android SDK was detected." should appear at the bottom. This means that it has detected the configured SDK.
SDK Components Setup

If you proceed in this state, you can set up by using the SDK already set up. Let's create an AVD with AVD Manager in the environment created in this way and check if it can be started.

Creating a separate user just for the emulator is a cumbersome task, but first you should isolate whether the problem with the user folder name can be solved. The added user can delete it cleanly when it is no longer needed.