跑虚拟机的时候就这样：
AVD Nexus_5X_API_24 is already running.
If that is not the case, delete the files at
C:\Users\liu\.android\avd/Nexus_5X_API_24.avd/*.lock
and try again.
跑手机就这样了：Installation failed with message Failed to establish session.
It is possible that this issue is resolved by uninstalling an existing version of the apk if it is present, and then re-installing.
WARNING: Uninstalling will remove the application data!
Do you want to uninstall the existing application?

就没人救救我吗

我也是升级了sdk就一直这样，难道是出bug了？

开发者选项把"启动MIUI优化"关掉就行了o(*￣▽￣*)ブ

打开USB调试，出现图中提示就可以了

6楼正解，顺便说下 点击版本号N次后就会出现开发者选项

楼主解决了吗？ 我的USB调试也不行啊

打开AVD Manager 有个stop 每个条目最右侧 下拉箭头 有个stop 停止就OK了 实在不行就删掉重新创建一个

跑虚拟机的时候就这样：
AVD Nexus_5X_API_24 is already running.
If that is not the case, delete the files at
C:\Users\liu\.android\avd/Nexus_5X_API_24.avd/*.lock
and try again看这句话，删除对应目录的那个*.lock文件看看

楼主问题解决了吗

能不能说一下方法

删除了相关文件夹，但是也是不行 错误提示还是一样

点击tools菜单栏，选择Android,然后点击avd manager，然后参考9楼答案。

6楼正解，顺便说下 点击版本号N次后就会出现开发者选项