diff --git a/src/cpptools.ts b/src/cpptools.ts
index 4f33c4638..d3d55df60 100644
--- a/src/cpptools.ts
+++ b/src/cpptools.ts
@@ -28,12 +28,15 @@ type StandardVersion = "c89" | "c99" | "c11" | "c17" | "c++98" | "c++03" | "c++1
 export interface DiagnosticsCpptools {
   isReady: boolean;
   hasCodeModel: boolean;
+  activeBuildType: string;
+  buildTypesSeen: string[];
   targetCount: number;
   executablesCount: number;
   librariesCount: number;
   targets: DiagnosticsTarget[];
   requests: string[];
   responses: cpt.SourceFileConfigurationItem[];
+  partialMatches: DiagnosticsPartialMatch[];
 }
 
 export interface DiagnosticsTarget {
@@ -41,6 +44,11 @@ export interface DiagnosticsTarget {
   type: TargetTypeString;
 }
 
+export interface DiagnosticsPartialMatch {
+  request: string;
+  matches: string | string[];
+}
+
 export interface CompileFlagInformation {
   extraDefinitions: string[];
   standard?: StandardVersion;
@@ -407,6 +415,9 @@ export class CppConfigurationProvider implements cpt.CustomConfigurationProvider
    */
   private _activeTarget: string|null = null;
 
+  private activeBuildType: string|null = null;
+  private buildTypesSeen = new Set<string>();
+
   /**
    * Create a source file configuration for the given file group.
    * @param fileGroup The file group from the code model to create config data for
@@ -431,11 +442,6 @@ export class CppConfigurationProvider implements cpt.CustomConfigurationProvider
       throw new MissingCompilerException();
     }
 
-    const buildType = opts.cache.get('CMAKE_BUILD_TYPE');
-    if (buildType) {
-      opts.activeBuildTypeVariant = buildType.as<string>();
-    }
-
     const targetFromToolchains = comp_toolchains?.target;
     const targetArchFromToolchains = targetFromToolchains ? parseTargetArch(targetFromToolchains) : undefined;
 
@@ -536,11 +542,23 @@ export class CppConfigurationProvider implements cpt.CustomConfigurationProvider
     // Reset the counters for diagnostics
     this.requests.clear();
     this.responses.clear();
+    this.buildTypesSeen.clear();
     this.targets = [];
 
     let hadMissingCompilers = false;
     this._workspaceBrowseConfiguration = {browsePath: []};
     this._activeTarget = opts.activeTarget;
+    this.activeBuildType = opts.activeBuildTypeVariant;
+    for (const config of opts.codeModelContent.configurations) {
+      this.buildTypesSeen.add(config.name);
+    }
+    if (this.buildTypesSeen.size > 0 && !this.buildTypesSeen.has(opts.activeBuildTypeVariant || "")) {
+      const configName = opts.codeModelContent.configurations[0].name;
+      log.warning(localize('build.type.out.of.sync',
+        "The build configurations generated do not contain the active build configuration. Using '{0}' for CMAKE_BUILD_TYPE instead of '{1}' to ensure that IntelliSense configurations can be found",
+        configName, opts.activeBuildTypeVariant));
+      opts.activeBuildTypeVariant = configName;
+    }
     for (const config of opts.codeModelContent.configurations) {
       // Update only the active build type variant.
       if (config.name === opts.activeBuildTypeVariant) {
@@ -596,11 +614,34 @@ export class CppConfigurationProvider implements cpt.CustomConfigurationProvider
   }
 
   getDiagnostics(): DiagnosticsCpptools {
+    const partialMatches: DiagnosticsPartialMatch[] = [];
+    for (const request of this.requests) {
+      const uri = vscode.Uri.parse(request);
+      const configuration = this._getConfiguration(uri);
+      if (!configuration) {
+        const fileName = path.basename(uri.fsPath);
+        const matches = [];
+        for (const [key, _] of this._fileIndex) {
+          if (path.basename(key) === fileName) {
+            matches.push(key);
+          }
+        }
+        if (matches.length === 1) {
+          partialMatches.push({ request, matches: matches.toString() });
+        } else if (matches.length > 1) {
+          partialMatches.push({request, matches});
+        }
+      }
+    }
+
     return {
       isReady: this.ready,
       hasCodeModel: this._fileIndex.size > 0,
+      activeBuildType: this.activeBuildType || "",
+      buildTypesSeen: [...this.buildTypesSeen.values()],
       requests: [...this.requests.values() ],
       responses: [...this.responses.values()],
+      partialMatches,
       targetCount: this.targets.length,
       executablesCount: this.targets.reduce<number>((acc, target) => target.type === 'EXECUTABLE' ? acc + 1 : acc, 0),
       librariesCount: this.targets.reduce<number>((acc, target) => target.type.endsWith('LIBRARY') ? acc + 1 : acc, 0),
diff --git a/src/extension.ts b/src/extension.ts
index 68f13c6b8..c1f83e56b 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -743,7 +743,19 @@ class ExtensionManager implements vscode.Disposable {
         if (drv) {
           drv.isMultiConfig = isMultiConfig;
         }
-        const actualBuildType = isMultiConfig && cmt.useCMakePresets ? cmt.buildPreset?.configuration || null : cmt.activeVariant;
+        const actualBuildType = (() => {
+          if (cmt.useCMakePresets) {
+            if (isMultiConfig) {
+              return cmt.buildPreset?.configuration || null;
+            } else {
+              const buildType = cache.get('CMAKE_BUILD_TYPE');
+              return buildType ? buildType.as<string>() : null; // Single config generators set the build type during config, not build.
+            }
+          } else {
+            return cmt.activeVariant;
+          }
+        })();
+
         const clCompilerPath = await findCLCompilerPath(env);
         this._configProvider.cpptoolsVersion = cpptools.getVersion();
         let codeModelContent;