diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/language/settings/providers/ScannerDiscoveryLegacySupport.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/language/settings/providers/ScannerDiscoveryLegacySupport.java
index c597d7b8b13..0372ba62cac 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/language/settings/providers/ScannerDiscoveryLegacySupport.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/language/settings/providers/ScannerDiscoveryLegacySupport.java
@@ -7,6 +7,7 @@
  *
  * Contributors:
  *     Andrew Gvozdev - initial API and implementation
+ *     Sergey Prigogin (Google)
  *******************************************************************************/
 
 package org.eclipse.cdt.core.language.settings.providers;
@@ -119,7 +120,11 @@ public class ScannerDiscoveryLegacySupport {
 	 */
 	public static void setLanguageSettingsProvidersFunctionalityEnabled(IProject project, boolean value) {
 		Preferences pref = getPreferences(project);
+		if (value == isLanguageSettingsProvidersFunctionalityEnabled(project))
+			return;
 		pref.putBoolean(DISABLE_LSP_PREFERENCE, !value);
+		// Scanner info provider have changed - clear the cached copy (http://bugs.eclipse.org/413357).
+		CCorePlugin.getDefault().resetCachedScannerInfoProvider(project);
 		try {
 			pref.flush();
 		} catch (BackingStoreException e) {
diff --git a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/core/CCorePlugin.java b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/core/CCorePlugin.java
index cd1d4b8081b..08e08afdfef 100644
--- a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/core/CCorePlugin.java
+++ b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/core/CCorePlugin.java
@@ -12,6 +12,7 @@
  *     Anton Leherbauer (Wind River Systems)
  *     oyvind.harboe@zylin.com - http://bugs.eclipse.org/250638
  *     Jens Elmenthaler - http://bugs.eclipse.org/173458 (camel case completion)
+ *     Sergey Prigogin (Google)
  *******************************************************************************/
 package org.eclipse.cdt.core;
 
@@ -1059,6 +1060,23 @@ public class CCorePlugin extends Plugin {
 		return provider;
 	}
 
+	/**
+	 * Clears cached scanner info provider for the given project so that the next call to
+	 * {@link #getScannerInfoProvider(IProject)} would return an up to date scanner info provider.
+	 *
+	 * @noreference This method is not intended to be referenced by clients.
+	 */
+	public void resetCachedScannerInfoProvider(IProject project) {
+		try {
+			QualifiedName scannerInfoProviderName = new QualifiedName(PLUGIN_ID, SCANNER_INFO_PROVIDER2_NAME);
+			project.setSessionProperty(scannerInfoProviderName, null);
+		} catch (CoreException e) {
+			if (project.isOpen()) {
+				log(e);
+			}
+		}
+	}
+
 	/**
 	 * Find {@link IScannerInfoProvider} registered as extension via extension point
 	 * org.eclipse.cdt.core.ScannerInfoProvider2.