Waiting for another flutter command to release the startup lock

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

killall -9 dart

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

taskkill /F /IM dart.exe

(You can read about taskkill flags in Windows here)

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Remove this file:

<YOUR FLUTTER FOLDER>/bin/cache/lockfile

This releases the occupied lock and makes you able to run other commands.

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In Windows :

Press: Ctrl + Alt + Delete

In task manager find out your editor such as VS Studio or Android Studio

In that Find "dart" and End that Task

Then close your editor

Open editor again

let editor to complete all things, after that run your query that will work

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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.

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I use a Mac with Visual Studio Code and this is what worked:

Shutdown your PC and switch it on again. Don't use the restart function. I restarted 2 times and it didn't work. Only shutdown worked.

PS: I tried out the following:

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

But they all didn't work.

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Exit from your IDE, then from start manager stop all dart related files(if any have).
Then go to
"FLUTTER DIRECTORY"/bin/cache/lockfile
and delete this lockfile

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

The difference between the 2 is explained here.

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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.

https://i.stack.imgur.com/kKLQD.png

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This also happens when you have opened the flutter project in the Editor. Close the Editor and re-run the command

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I tried all previous suggestions but without benefit. Finally when I connect my pc to internet and wait flutter to release then 5 minutes solved

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In VS code run

flutter clean

in the terminal. This fixed my issue.

https://i.stack.imgur.com/S98HX.png

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

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

Below is the final command that worked for me

rm -rf <flutter_dir>bin/cache/.upgrade_lock

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

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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.

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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).

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If you are using Windows, you can open the task manager and under the 'Processes' tab search for processes named 'dart'. End all those tasks.

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In Android Studio, It's Work for me

Stop your app if it still runs on the phone or disconnect the your testing device.

Then try to install the package again.

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There are some action to do:

1- in pubspec.yaml press "packages get" or in terminal type " flutter packages get" and wait seconds.

if this doesn't work :

2-type flutter clean then do step(1)

if this doesn't work too :

3-type killtask /f /im dart.exe

if this doesn't work too :

4- close android studio and then restart your pc.

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Turn off Android Studio. Open flutter installation directory /bin/cache. Delete lockfile. At this point, you can execute the flutter related command on the command line to solve the problem perfectly.

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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

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Restart your computer or simple logout from the current user and login again.

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I also faced same issue i followed the best and the easiest way

Environment : Windows

IDE : Android Studio

Tools>flutter(last option)> select flutter clean

after flutter clean finished you all set and good to go.

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Did most of the previous solutions but it didn't work for me so i just left the laptop connected to the internet with VS-code opened then i switched if off for a while and put it back on and it worked

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It seems like a network issue. I turned off my wi-fi and connected my laptop on a 4G connection by my phone an it works in 5,9s

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I just left the terminal open for a minute. then it started working fine again.

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On Mac remove hidden file: <FLUTTER_HOME>/bin/cache/.upgrade_lock

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This worked for me:

Restart your IDE Fun the following command flutter clean

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Just Do that!!!

Do not create a project within the Flutter SDK directory. Create your project in another directory. Then It will work properly If you can solve this problem please Rate this answer. Thanks for your support

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Just type this on android studio terminal and will work again!

flutter run

:)

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