我也遇到了这个问题，并在Google上进行了搜索，将其重定向到此问题.我的是xcode10我的工作如下

I also have this issue and googled this, which redirect to this question. Mine was xcode10 What i have done is as follows

1. 退出模拟器& Xcode.
2. 打开Activity monitor，选择cpu选项并搜索sim，杀死显示为结果的所有过程.
3. 然后启动终端并运行sudo xcrun simctl erase all.它将删除所有模拟器的所有内容.按内容显示，如果您登录的某个地方的密码将丢失，那么该模拟器中安装的所有开发人员应用程序都将消失.

1. Quit the simulator & Xcode.
2. Opened Activity monitor, selected cpu option and search for sim, killing all the process shown as result.
3. Then fired up the terminal and run sudo xcrun simctl erase all. It will delete all content of all simulators. By content if you logged in somewhere password will be gone, all developer apps installed in that simulator will be gone.

做这些解决了我的问题.希望对您有所帮助.

Doing these resolved my issue. Hope it helps.