Error on line 1, column 1 of pubspec.lock: Unexpected character
The file pubspec.lock is a generated file, so you can delete it and then regenerate it.
Delete pubspec.lock.
Run the following command:
flutter pub getor
flutter pub upgradeNotes on pub upgrade (you could probably skip the delete step).
Delete the file at flutter/packages/flutter_tools/pubspec.lock then try flutter pub upgrade again.
You may have interrupted the upgrade process before it finished hence the file became invalid.
I took the same error,but this error was coming from my main folder.in this path "C:\Users"yourusername"\AppData\Local\Pub\Cache\global_packages\devtools"I deleted the file and I started app. file has been by itself created and problem solved.