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"Hot Reload received invalid response" ... "Error while starting Kernel isolate task" on hot reload #64758
Description
Steps to Reproduce
- Run app via connected device
- Wait until app is running
- Doesn't matter if I make changes or don't make changes to the code
- Hot reload
Expected results:
Expecting hot reload to work
Actual results:
Receive this error about half of the time:
Performing hot reload...
Syncing files to device Pixel XL...
Hot reload received invalid response: {type: ReloadReport, success: false, notices: [{type: ReasonForCancelling, message: Error while starting Kernel isolate task}]}
Logs
[√] Flutter (Channel stable, 1.20.2, on Microsoft Windows [Version 6.3.9600], locale en-US)
• Flutter version 1.20.2 at C:\_Data\FlutterSDK\flutter
• Framework revision bbfbf1770c (2 weeks ago), 2020-08-13 08:33:09 -0700
• Engine revision 9d5b21729f
• Dart version 2.9.1
[√] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
• Android SDK at C:\Users\AA\AppData\Local\Android\sdk
• Platform android-29, build-tools 29.0.3
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
• All Android licenses accepted.
[√] Android Studio (version 3.6)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin version 48.1.1
• Dart plugin version 192.8052
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
[√] IntelliJ IDEA Community Edition (version 2019.3)
• IntelliJ at C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2019.3.4
• Flutter plugin version 45.0.2
• Dart plugin version 193.6911.31
[√] VS Code, 64-bit edition (version 1.48.2)
• VS Code at C:\Program Files\Microsoft VS Code
• Flutter extension version 3.13.2
[√] Connected device (1 available)
• Pixel XL (mobile) • HT7650201635 • android-arm64 • Android 10 (API 29)
• No issues found!
Please let me know if there's something else I can do to help diagnose this issue. I can reproduce it consistently on my machine.
Performing a hot restart after receiving the error successfully re-runs the app. The error happens regardless of if I change any files or not, or how long it has been since running the app.
Activity
pedromassangocode commentedon Aug 28, 2020
Hi @allanchao
I cannot reproduce this issue on latest
betachannel.Can you upgrade to
betaand try againflutter channel betaflutter upgrade --forceflutter doctor -vallanchao commentedon Aug 29, 2020
Hello, I followed your instructions to upgrade to beta, and was able to reproduce the error on my machine. Anything else I can do? Is there like a hot-reload-with-verbose-log command that I can run?
By the way, usually what happens, is I can use hot reload 1-3 times successfully before it suddenly stops working. As mentioned previously, it has no relation to whether I change anything in the code or not, or the timing of the reloads.
pedromassangocode commentedon Aug 31, 2020
Hi @allanchao
Hmm, please try one more time with the
masterchannel.Upgrade to
masterand try again please:flutter channel masterflutter upgrade --forceflutter doctor -vallanchao commentedon Sep 1, 2020
I followed your instructions to upgrade to master, and tried it out, and it still bugged out.
bug
flutter doctor
I also noticed something new this time. I don't know if it's always been the case and I just noticed it, or if it's new, but sometimes I do the hot reload, and it appears in the console as if it succeeded, but in reality it did not.
Despite the message, it did not reload. Visually nothing changed on the app running on the device.
allanchao commentedon Sep 1, 2020
I'm not sure if this is relevant, but I saw "analysis server terminated" and clicked on view logs, and this came up. I wonder if the stream being destroyed has something to do with the hot reload failing? Also, I can confirm this error happens in both visual studio code and android studio (same flutter sdk on master channel).
Here's the full log
54 remaining items
mozerrr commentedon Oct 29, 2021
Same issue without any anti-virus software.
apple silicon m1
macos 12.0.1 (21A559) / same was on big sur
simulator iphone 12 ios 15.0
flutter stable 1.22.6
Android Studio Bumblebee | 2021.1.1 Beta 1
Atharva17062002 commentedon Jan 12, 2023
Same issue without any anti-virus software.
apple silicon m1
macos 13.0.1
simulator pixel 5 Android Tiramisu /
flutter stable 3.7.0
Android Studio Dolphin | 2021.3.1
LinarAI commentedon Oct 16, 2023
win11 hot reload was rejected:
Performing hot reload...
Syncing files to device Windows...
Hot reload was rejected:
Error while starting Kernel isolate task.
Try performing a hot restart instead.
Zhoucheng133 commentedon May 13, 2024
Hot reload works on Android & Web but not works on Windows app:
Hot reload was rejected: Error while starting Kernel isolate task. Try performing a hot restart instead.I tried:
Zhoucheng133 commentedon May 26, 2024
For Windows desktop develop,
Hot reload was rejectedmay because your user folder named with non-English charactors. Create an English-only username to fix it!Eglusaxie commentedon Aug 7, 2024
this solution works perfect for me.you are god damn right.i'll never use chinese username account anymore.
ps6067966 commentedon May 18, 2025
Hot reload was rejected:
Error while starting Kernel isolate task.
Try performing a hot restart instead.
Getting same in macbook m4.
[engine] Support UTF-8 paths in Windows filesystem and path APIs (flu…
github-actions commentedon Sep 8, 2026
This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of
flutter doctor -vand a minimal reproduction of the issue.