Waiting for another flutter command to release the startup lock

1. Delete **pubspec.lock** file
2. Run "**flutter pub get**" from terminal **or** editor shortcut ("*get packages*" **AndroidStudio** or [this logo][1] **Visual Studio**) in pubspec.yaml file.
3. Wait for download.
4. If it doesn't work relaunch your editor then repeat **step 2.**.


[1]:

Most are saying `killall -9 dart` but nobody mentioned `pkill -f dart` which worked for me.

The difference between the 2 is explained [here](

[To see links please register here]

).

1. Turn off Android Studio.

2. Open flutter installation directory /bin/cache.

3. Delete lockfile.

4. At this point, you can execute the flutter related command on the command line to solve the problem perfectly.

In VS code run

```
flutter clean
```

in the terminal. This fixed my issue.

[![code image][1]][1]


[1]:

You can remove flutter and "install again", so fastest way is to:

# 1) Check where you have `flutter` (as executable)

To check it, you can run:
```
which flutter
```
And you can expect such output:
```
/your_user/your_path/flutter/bin/flutter
```

# 2) Go to this directory

Above path is directly to flutter, but we would like to go to directory so "one earlier" in path:
```
cd /your_user/your_path/flutter/bin
```

# 3) Check is it `git` repository
**It should be**, but it's worth to check.

Run one of the git command e.g.
```
git status
```

or
```
git branch
```

When it's git repository you will receive some info about it or correct list of branches.

# 4) Remove all of the files
```
rm -R *
```

# 5) "revert" removal to have only necessary files:

```
git co -- .
```

# 6) Voila!
You can run just `flutter version` and commands should work (and Flutter will fetch some necessary data).

Nothing of ALL these answers didn't helped me.

The only one solution was to remove whole flutter stuff (and reinstall flutter from git):

<flutter directory>
<user>/.flutter_tool_state
<user>/.dart
<user>/.pub-cache
<user>/.dartServer
<user>/.flutter

I have the same issue, I tried all the above solutions, but none of them worked for me. Then I searched the keywords in flutter directory, and found the following code. So I tried to delete `bin/cache/.upgrade_lock`, and it worked finally.

[![enter image description here][1]][1]


[1]:

For me, the issue's root cause on my Mac device was a version of the flock binary it was not expecting. Removing it from the path did the trick; probably a BSD vs GNU syntax issue.

You can try to kill all `flutter` processes.

TL;DR - go to point `4)`


# 1) List of the processes:
```
ps aux
```

# 2) Search name containing with `flutter`:
```
ps aux | grep flutter
```

where output can be like there:
```
stackoverflow 16697 1.5 0.0 4288316 704 ?? S 10:02PM 0:15.80 bash /flutter_path/flutter/bin/flutter --no-color build apk
stackoverflow 2800 1.5 0.0 4288316 704 ?? S 9:59PM 0:18.49 bash /flutter_path/flutter/bin/flutter --no-color pub get
stackoverflow 1215 1.5 0.0 4280124 700 ?? S 9:58PM 0:18.89 bash /flutter_path/flutter/bin/flutter --no-color config --machine
stackoverflow 8449 1.5 0.0 4296508 716 ?? S 10:00PM 0:17.20 bash /flutter_path/flutter/bin/flutter --no-color pub get
stackoverflow 1326 1.4 0.0 4288316 708 ?? S 9:58PM 0:18.97 bash /flutter_path/flutter/bin/flutter daemon
stackoverflow 16687 0.0 0.0 4279100 820 ?? S 10:02PM 0:00.01 bash /flutter_path/flutter/bin/flutter --no-color build apk
stackoverflow 8431 0.0 0.0 4288316 804 ?? S 10:00PM 0:00.02 bash /flutter_path/flutter/bin/flutter --no-color pub get
stackoverflow 2784 0.0 0.0 4288316 704 ?? S 9:59PM 0:00.01 bash /flutter_path/flutter/bin/flutter --no-color pub get
stackoverflow 1305 0.0 0.0 4280124 712 ?? S 9:58PM 0:00.01 bash /flutter_path/flutter/bin/flutter daemon
stackoverflow 1205 0.0 0.0 4279100 788 ?? S 9:58PM 0:00.01 bash /flutter_path/flutter/bin/flutter --no-color config --machine
stackoverflow 11416 0.0 0.0 4268176 536 s000 R+ 10:18PM 0:00.00 grep --color flutter
```

# 3) Get processes ID

We need content from **second** column (from above output):

```
ps aux | grep flutter | awk '{print $2}'
```

# 4 a) Kill "automatically":

To list, search and kill all of them you can use
```
kill $(ps aux | grep flutter | grep -v grep | awk '{print $2}')
```
(you can run it also with `sudo`)

or

```
ps aux | grep flutter | grep -v grep | awk '{print $2}' | xargs kill -15
```


# 4 b) Kill manually

You can kill processes one-by-one using:
```
sudo kill -15 <process_ID>
```
e.g. to kill process with id `13245` use:
```
sudo kill -15 13245
```

If `-15` will not work, you can try `-2` or `-1`.

Final option it is `-9` which should not be used because it prevents the process from doing any cleanup work.

In my case, the following command in Terminal helped (as suggested by [Günter Zöchbauer's comment](

[To see links please register here]

)):

```
killall -9 dart
```

On Windows, run the following in a Command Prompt or PowerShell window (as suggested by [upupming's comment](

[To see links please register here]

)):

```
taskkill /F /IM dart.exe
```

(You can read about taskkill flags in Windows [here](

[To see links please register here]

))