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 8bf5b3832b1..2ac8defa26c 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
@@ -62,6 +62,22 @@ public class ScannerDiscoveryLegacySupport {
 		}
 	}
 
+	/**
+	 * Checks if Language Settings functionality is defined for given project in preferences.
+	 *
+	 * @param project - project to check the preference
+	 * @return {@code true} if functionality is defined
+	 *
+	 * @noreference This method is temporary and not intended to be referenced by clients.
+	 * 
+	 * @since 5.4.1
+	 */
+	public static boolean isLanguageSettingsProvidersFunctionalityDefined(IProject project) {
+		Preferences pref = getPreferences(project);
+		String value = pref.get(DISABLE_LSP_PREFERENCE, null);
+		return value != null;
+	}
+
 	/**
 	 * Checks if Language Settings functionality is enabled for given project.
 	 *
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/language/settings/providers/LanguageSettingsProvidersSerializer.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/language/settings/providers/LanguageSettingsProvidersSerializer.java
index d5fb7509e71..b9e6a1bf2b6 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/language/settings/providers/LanguageSettingsProvidersSerializer.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/language/settings/providers/LanguageSettingsProvidersSerializer.java
@@ -1172,7 +1172,6 @@ public class LanguageSettingsProvidersSerializer {
 							} else {
 								providers.add(LanguageSettingsManager.getExtensionProviderCopy(id, true));
 							}
-
 						}
 						((ILanguageSettingsProvidersKeeper) cfgDescription).setLanguageSettingProviders(providers);
 					}
@@ -1187,6 +1186,11 @@ public class LanguageSettingsProvidersSerializer {
 					}
 				}
 			}
+			
+			if (!ScannerDiscoveryLegacySupport.isLanguageSettingsProvidersFunctionalityDefined(project)) {
+				// if not yet defined by user - set preference to tell if this is legacy .cproject (i.e. no LSP storageElement)
+				ScannerDiscoveryLegacySupport.setLanguageSettingsProvidersFunctionalityEnabled(project, storageElement != null);
+			}
 
 		}
 	}