Невозможно обновить DART SDK. повторно
restart your pc and delete flutter folder in C directroy then reinistall flutter and run flutter doctor
Prof. EY
restart your pc and delete flutter folder in C directroy then reinistall flutter and run flutter doctor Add below path to Environment variable
User Variables
C:\flutter\bin; C:\Windows\System32
%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\
System Variables
C:\flutter\bin
C:\Windows\System32\