Application Insights Extension Installer Bug Can Result in Lost Custom App Settings – Awareness

A recent bug might have deleted custom App settings that you had in your Azure web apps. It affects Azure web apps where you recently installed Application Insights. We’re sorry for this. We’ve fixed the bug now, but you might need to re-enter your custom settings.

You need to check your Azure web apps, and re-enter your custom Application Settings if necessary. See the screenshot below. If you use automated scripts to manage these settings, please be sure to add the APPINSIGHTS_INSTRUMENTATIONKEY into the settings you deploy.




Portal experience which offers this extension to be installed:



What happened?

A recent version of the Application Insights extension installer for Azure web apps deleted any custom App Settings.
We have fixed the root cause for this, and are sorry for the trouble this may have caused.


Why did this happen?

  • Instead of appending the Application Insights instrumentation key to the settings, we overwrote the settings. And thereby wiped out any custom app settings you previously had.
  • Yes, this was dumb.

Why was this not found before release?

  • We used test applications which did not have custom app settings. Yeah, that was dumb, too.

How will we prevent this going forward?

  • We have reviewed and filled the gaps in automated and manual test coverage of the Application Insights extension installer.
  • We have added a web app with custom app settings into our collection of apps used in prerelease test passes.
  • We have added an internal dogfooding step where we validate changes on ourselves before wider release.

Your trust and use of Application Insights is very important to us, and we will strive harder to earn and keep it. We apologize for any disruption and inconvenience this may have caused.


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