"Could not connect to lockdownd" while attempting to run flutter app

Disconnect all iOS devices, then:

brew uninstall ideviceinstallerbrew uninstall libimobiledevicebrew install --HEAD libimobiledevicebrew link --overwrite libimobiledevicebrew install --HEAD  ideviceinstallerbrew link --overwrite ideviceinstallersudo rm -rf /var/db/lockdown/*

Connect an iOS device, and choose "Trust" when prompted, after that:

sudo chmod -R 777 /var/db/lockdown/

This workaround worked for me when loosing the connection:

• close everything (Visual Studio Code, Xcode, Simulator)
• disconnect any physical device
• Start Visual Studio Code
• connect a physical IOS phone
• Start XCode
• build from XCode (it will work)
• Disconnect your physical device
• Start without debug
• You will be prompted to connect to a device

and from there it worked again!

This just to help to debug the loos of connection bug. I have also observed that it begins just after the "stop debugging" command from Visual Studio Code.

I was having similar issues, and resolved them using the below. Hopefully this will help you. flutter doctor was telling me the answers, but they were a bit buried. Look for something like this:

[-] iOS toolchain - develop for iOS devices (Xcode 8.3.3)    • Xcode at /Applications/Xcode.app/Contents/Developer    • Xcode 8.3.3, Build version 8E3004b    ✗ libimobiledevice and ideviceinstaller are not installed or require updating. To update, run:        brew uninstall --ignore-dependencies libimobiledevice        brew install --HEAD libimobiledevice        brew install ideviceinstaller    • ios-deploy 1.9.1    ✗ ios-deploy out of date (1.9.2 is required). To upgrade:        brew upgrade ios-deploy    • CocoaPods version 1.2.0

There are four brew commands in there to run. When I did them, this problem disappeared for me. Good luck!