diff --git a/maven-core/src/main/java/org/apache/maven/ReactorReader.java b/maven-core/src/main/java/org/apache/maven/ReactorReader.java
index 42cccba15640..edba95447f00 100644
--- a/maven-core/src/main/java/org/apache/maven/ReactorReader.java
+++ b/maven-core/src/main/java/org/apache/maven/ReactorReader.java
@@ -279,9 +279,8 @@ private boolean hasBeenPackagedDuringThisSession(MavenProject project) {
     }
 
     private Path relativizeOutputFile(final Path outputFile) {
-        Path projectBaseDirectory =
-                Paths.get(session.getRequest().getMultiModuleProjectDirectory().toURI());
-        return projectBaseDirectory.relativize(outputFile);
+        Path rootDirectory = session.getRequest().getRootDirectory();
+        return rootDirectory.relativize(outputFile);
     }
 
     /**
@@ -445,7 +444,7 @@ private Path getArtifactPath(Artifact artifact) {
 
     private Path getProjectLocalRepo() {
         if (projectLocalRepository == null) {
-            Path root = session.getRequest().getMultiModuleProjectDirectory().toPath();
+            Path root = session.getRequest().getRootDirectory();
             List<MavenProject> projects = session.getProjects();
             if (projects != null) {
                 projectLocalRepository = projects.stream()
diff --git a/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java b/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java
index 1216f081b291..921579f1c29f 100644
--- a/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java
+++ b/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java
@@ -61,7 +61,7 @@ public MultiModuleCollectionStrategy(ModelLocator modelLocator, ProjectsSelector
 
     @Override
     public List<MavenProject> collectProjects(MavenExecutionRequest request) throws ProjectBuildingException {
-        File moduleProjectPomFile = getMultiModuleProjectPomFile(request);
+        File moduleProjectPomFile = getRootProject(request);
         List<File> files = Collections.singletonList(moduleProjectPomFile.getAbsoluteFile());
         try {
             List<MavenProject> projects = projectsSelector.selectProjects(files, request);
@@ -96,24 +96,24 @@ public List<MavenProject> collectProjects(MavenExecutionRequest request) throws
         }
     }
 
-    private File getMultiModuleProjectPomFile(MavenExecutionRequest request) {
-        File multiModuleProjectDirectory = request.getMultiModuleProjectDirectory();
-        if (request.getPom().getParentFile().equals(multiModuleProjectDirectory)) {
+    private File getRootProject(MavenExecutionRequest request) {
+        File rootDirectory = request.getRootDirectory().toFile();
+        if (request.getPom().getParentFile().equals(rootDirectory)) {
             return request.getPom();
         } else {
-            File multiModuleProjectPom = modelLocator.locateExistingPom(multiModuleProjectDirectory);
-            if (multiModuleProjectPom == null) {
+            File rootProjectPom = modelLocator.locateExistingPom(rootDirectory);
+            if (rootProjectPom == null) {
                 LOGGER.info(
                         "Maven detected that the requested POM file is part of a multi-module project, "
-                                + "but could not find a pom.xml file in the multi-module root directory '{}'.",
-                        multiModuleProjectDirectory);
+                                + "but could not find a pom.xml file in the root directory '{}'.",
+                        rootDirectory);
                 LOGGER.info(
                         "The reactor is limited to all projects under: {}",
                         request.getPom().getParent());
                 return request.getPom();
             }
 
-            return multiModuleProjectPom;
+            return rootProjectPom;
         }
     }