Error: "Adb connection Error:An existing connection was forcibly closed by the remote host"

Well, its not compulsory to restart the emulator you can also reset adb from eclipse itself.

1.) Go to DDMS and there is a reset adb option, please see the image below.

2.) You can restart adb manually from command prompt

  run->cmd->your_android_sdk_path->platform-tools>

Then write the below commands.

adb kill-server - To kill the server forcefully

adb start-server - To start the server

UPDATED:

F:\android-sdk-windows latest\platform-tools>adb kill-server

F:\android-sdk-windows latest\platform-tools>adb start-server
* daemon not running. starting it now on port 5037 *
* daemon started successfully *

It seems this issue has no exact solution, because the cause of this issue is not same for everyone. However, if you have faced this issue recently in Android Studio Bumblebee (2021.1.1) after updating from Arctic Fox, then the problem might have happened due to adb mDNS for wireless debugging.

To solve this issue, disable mDNS for wireless debugging from here:

Android Studio > Settings > Build, Execution, Deployment > Debugger > Untick "Enable adb mDNS for wireless debugging"

Change to another USB port works for me. I tried reset ADB, but problem still there.

Looks like the installed driver was in bad state. Here is what I did to make it work:

1. Delete the device from Device Manager.
2. Rescan for hardware changes.
3. "Slate 21" will show up with "Unknown driver" status.
4. Click on "Update Driver" and select /extras/google/usb_driver
5. Device Manager will find the driver and warn you about installing it. Select "Yes."

This time the device got installed properly.

Note that I didn't have to modify winusb.inf file or update any other driver.

Hope this helps.

In my case, resetting ADB didn't make a difference. I also needed to delete my existing virtual devices, which were pretty old, and create new ones.