Waiting for another flutter command to release the startup lock

Question

When I run my flutter application it show

Waiting for another flutter command to release the startup lock

this messages and not

Answer 1

I have tried all of below steps, but none worked.

1. Delete lockfile;
2. Run killall -9 dart;
3. Restart my PC.

Below is the final command that worked for me

rm -rf bin/cache/.upgrade_lock