升級xcode10遇到unable to launch ***，解決辦法
週末媳婦看我手機是ios11.x，她要給我升級到12，本人大喊不要，還是被她給升了。
週一上班了，發現我的xcode9.x不能在ios12上面除錯。 必須先升級macOS到10.14，再升級xcode到10。蘋果真是毀人不倦。
然後發生了一些問題挨個折騰：
【問題1】證書籤名需要重新匯入。 同事說xcode有問題，必須先設定成"automatically manage signing",再選擇provisioning profile才能重新載入成功。 從鑰匙串刪掉原有的開發祕鑰，將簽名檔案xxxx.mobileprovision和密碼.p12分別雙擊，重新載入簽名祕鑰。
【問題2】每次執行都要輸入管理員密碼的問題，將開發者鑰匙串改成所有人都可以訪問解決。
【問題3】更讓人鬱悶“unable to launch xxxx”，網上搜了一大堆各種辦法。折騰了一天十幾個小時（水平太菜了），才找到解決辦法。
I was having this problem while using Xcode 9.2 and iOS 11.2. After much googling, the only thing that solved all of my issues was turning off "Debug executable" in my scheme. This can be found under Product > Scheme > Edit Scheme > Run (on the left menu).
Prior to this, I tried a lot of different solutions including deleting my derived data, restarting my computer, and switching the launch in my scheme to "Wait for executable to be launched" instead of "Automatically". Switching the launch setting in my scheme allowed the app to launch on my phone, but the Xcode debugger and safari debugger still would not connect to my app.