diff --git a/server/src/main/java/org/elasticsearch/env/NodeEnvironment.java b/server/src/main/java/org/elasticsearch/env/NodeEnvironment.java
index 745820348a4ec..73ddbce5f82df 100644
--- a/server/src/main/java/org/elasticsearch/env/NodeEnvironment.java
+++ b/server/src/main/java/org/elasticsearch/env/NodeEnvironment.java
@@ -329,6 +329,9 @@ private static boolean upgradeLegacyNodeFolders(Logger logger, Settings settings
                         if (Files.isDirectory(nodeLockIdPath) && fileName.chars().allMatch(Character::isDigit)) {
                             int nodeLockId = Integer.parseInt(fileName);
                             nodeLockIds.add(nodeLockId);
+                        } else if (FileSystemUtils.isDesktopServicesStore(nodeLockIdPath) == false) {
+                            throw new IllegalStateException("unexpected file/folder encountered during data folder upgrade: " +
+                                nodeLockIdPath);
                         }
                     }
                 }
diff --git a/server/src/test/java/org/elasticsearch/env/NodeEnvironmentIT.java b/server/src/test/java/org/elasticsearch/env/NodeEnvironmentIT.java
index c5d7dd5bb61e1..f49b3b45aad53 100644
--- a/server/src/test/java/org/elasticsearch/env/NodeEnvironmentIT.java
+++ b/server/src/test/java/org/elasticsearch/env/NodeEnvironmentIT.java
@@ -162,8 +162,6 @@ public void testUpgradeDataFolder() throws IOException, InterruptedException {
                             }
                         }
                     }
-                    IOUtils.fsync(targetPath, true);
-                    IOUtils.fsync(path, true);
                 } catch (IOException e) {
                     throw new UncheckedIOException(e);
                 }
@@ -173,14 +171,24 @@ public void testUpgradeDataFolder() throws IOException, InterruptedException {
 
         // create extra file/folder, and check that upgrade fails
         if (dataPaths.isEmpty() == false) {
-            final Path badFile = Files.createTempFile(randomFrom(dataPaths).resolve("nodes").resolve("0"), "bad", "file");
+            final Path badFileInNodesDir = Files.createTempFile(randomFrom(dataPaths).resolve("nodes"), "bad", "file");
             IllegalStateException ise = expectThrows(IllegalStateException.class, () -> internalCluster().startNode(dataPathSettings));
             assertThat(ise.getMessage(), containsString("unexpected file/folder encountered during data folder upgrade"));
+            Files.delete(badFileInNodesDir);
+
+            final Path badFolderInNodesDir = Files.createDirectories(randomFrom(dataPaths).resolve("nodes").resolve("bad-folder"));
+            ise = expectThrows(IllegalStateException.class, () -> internalCluster().startNode(dataPathSettings));
+            assertThat(ise.getMessage(), containsString("unexpected file/folder encountered during data folder upgrade"));
+            Files.delete(badFolderInNodesDir);
+
+            final Path badFile = Files.createTempFile(randomFrom(dataPaths).resolve("nodes").resolve("0"), "bad", "file");
+            ise = expectThrows(IllegalStateException.class, () -> internalCluster().startNode(dataPathSettings));
+            assertThat(ise.getMessage(), containsString("unexpected file/folder encountered during data folder upgrade"));
             Files.delete(badFile);
 
             final Path badFolder = Files.createDirectories(randomFrom(dataPaths).resolve("nodes").resolve("0").resolve("bad-folder"));
             ise = expectThrows(IllegalStateException.class, () -> internalCluster().startNode(dataPathSettings));
-            assertThat(ise.getMessage(), containsString("unexpected folder encountered during data folder upgrad"));
+            assertThat(ise.getMessage(), containsString("unexpected folder encountered during data folder upgrade"));
             Files.delete(badFolder);
 
             final Path conflictingFolder = randomFrom(dataPaths).resolve("indices");