diff --git a/src/plugins/cmakeprojectmanager/fileapireader.cpp b/src/plugins/cmakeprojectmanager/fileapireader.cpp
index 53239b40d68..df542f13dfc 100644
--- a/src/plugins/cmakeprojectmanager/fileapireader.cpp
+++ b/src/plugins/cmakeprojectmanager/fileapireader.cpp
@@ -40,9 +40,9 @@ FileApiReader::FileApiReader()
     : m_lastReplyTimestamp()
 {
     QObject::connect(&m_watcher,
-                     &FileSystemWatcher::directoryChanged,
+                     &FileSystemWatcher::fileChanged,
                      this,
-                     &FileApiReader::handleReplyDirectoryChange);
+                     &FileApiReader::handleReplyIndexFileChange);
 }
 
 FileApiReader::~FileApiReader()
@@ -60,11 +60,7 @@ void FileApiReader::setParameters(const BuildDirParameters &p)
     m_parameters = p;
     qCDebug(cmakeFileApiMode) << "Work directory:" << m_parameters.buildDirectory.toUserOutput();
 
-    FileApiParser::setupCMakeFileApi(m_parameters.buildDirectory);
-
-    const FilePath replyDirectory = FileApiParser::cmakeReplyDirectory(m_parameters.buildDirectory);
-    if (!m_watcher.watchesDirectory(replyDirectory))
-        m_watcher.addDirectory(replyDirectory.path(), FileSystemWatcher::WatchAllChanges);
+    setupCMakeFileApi();
 
     resetData();
 }
@@ -351,6 +347,15 @@ void FileApiReader::writeConfigurationIntoBuildDirectory(const QStringList &conf
     QTC_ASSERT_EXPECTED(settingsFile.writeFileContents(contents), return);
 }
 
+void FileApiReader::setupCMakeFileApi()
+{
+    FileApiParser::setupCMakeFileApi(m_parameters.buildDirectory);
+
+    const FilePath replyIndexfile = FileApiParser::scanForCMakeReplyFile(m_parameters.buildDirectory);
+    if (!replyIndexfile.isEmpty() && !m_watcher.watchesFile(replyIndexfile))
+        m_watcher.addFile(replyIndexfile.path(), FileSystemWatcher::WatchAllChanges);
+}
+
 QString FileApiReader::cmakeGenerator() const
 {
     return m_cmakeGenerator;
@@ -403,16 +408,13 @@ void FileApiReader::cmakeFinishedState(int exitCode)
     if (m_lastCMakeExitCode != 0)
         makeBackupConfiguration(false);
 
-    FileApiParser::setupCMakeFileApi(m_parameters.buildDirectory);
-
-    m_watcher.addDirectory(FileApiParser::cmakeReplyDirectory(m_parameters.buildDirectory).path(),
-                           FileSystemWatcher::WatchAllChanges);
+    setupCMakeFileApi();
 
     endState(FileApiParser::scanForCMakeReplyFile(m_parameters.buildDirectory),
              m_lastCMakeExitCode != 0);
 }
 
-void FileApiReader::handleReplyDirectoryChange(const QString &directory)
+void FileApiReader::handleReplyIndexFileChange(const QString &indexFile)
 {
     if (m_isParsing)
         return; // This has been triggered by ourselves, ignore.
@@ -422,7 +424,7 @@ void FileApiReader::handleReplyDirectoryChange(const QString &directory)
     if (dir.isEmpty())
         return; // CMake started to fill the result dir, but has not written a result file yet
     QTC_CHECK(dir.isLocal());
-    QTC_ASSERT(dir.path() == directory, return);
+    QTC_ASSERT(dir == FilePath::fromString(indexFile).parentDir(), return);
 
     if (m_lastReplyTimestamp.isValid() && reply.lastModified() > m_lastReplyTimestamp) {
         m_lastReplyTimestamp = reply.lastModified();
diff --git a/src/plugins/cmakeprojectmanager/fileapireader.h b/src/plugins/cmakeprojectmanager/fileapireader.h
index de56ad900d8..56908313a5f 100644
--- a/src/plugins/cmakeprojectmanager/fileapireader.h
+++ b/src/plugins/cmakeprojectmanager/fileapireader.h
@@ -78,10 +78,11 @@ private:
     void startCMakeState(const QStringList &configurationArguments);
     void cmakeFinishedState(int exitCode);
 
-    void handleReplyDirectoryChange(const QString &directory);
+    void handleReplyIndexFileChange(const QString &indexFile);
     void makeBackupConfiguration(bool store);
 
     void writeConfigurationIntoBuildDirectory(const QStringList &configuration);
+    void setupCMakeFileApi();
 
     std::unique_ptr<CMakeProcess> m_cmakeProcess;