Waiting for another flutter command to release the startup lock

Issue

When I run my flutter application it show

Waiting for another flutter command to release the startup lock

this messages and not proceed further.

Solution

In my case, following command in Terminal helped (as suggested by Günter):

killall -9 dart

On Windows (as suggested by upupming):

taskkill /F /IM dart.exe

Answered By - Sukhi