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Documentation/compatibility/ServiceBase-doesnt-propagate-OnStart-exceptions.md

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+## ServiceBase doesn't propagate OnStart exceptions
+
+### Scope
+
+Minor
+
+### Version Introduced
+
+4.7.1
+
+### Source Analyzer Status
+
+NotPlanned
+
+### Change Description
+
+In the .NET Framework 4.7 and earlier versions, exceptions thrown on service startup are not propagated to the caller of <xref:System.ServiceProcess.Servicebase.Run?displayProperty=nameWithType>.
+
+Starting with applications that target the .NET Framework 4.7.1, the runtime propagates exceptions to <xref:System.ServiceProcess.Servicebase.Run?displayProperty=nameWithType> for services that fail to start.
+
+- [x] Quirked
+- [ ] Build-time break
+
+### Recommended Action
+On service start, if there is an exception, that exception will be propagated. This should help diagnose cases where services fail to start.
+
+If this behavior is undesirable, you can opt out of it by adding the following <AppContextSwitchOverrides> element to the <runtime> section of your application configuration file:
+
+```xml
+<AppContextSwitchOverrides value="Switch.System.ServiceProcess.DontThrowExceptionsOnStart=true" />
+```
+
+If your application targets an earlier version than 4.7.1 but you want to have this behavior, add the following <AppContextSwitchOverrides> element to the <runtime> section of your application configuration file:
+
+```xml
+<AppContextSwitchOverrides value="Switch.System.ServiceProcess.DontThrowExceptionsOnStart=false" />
+```
+
+### Affected APIs
+* `M:System.ServiceProcess.ServiceBase.Run`