diff --git a/sdk/lib/fslib/vfatlib/vfatlib.c b/sdk/lib/fslib/vfatlib/vfatlib.c
index 8db6e8a11af..82c1282fbf0 100644
--- a/sdk/lib/fslib/vfatlib/vfatlib.c
+++ b/sdk/lib/fslib/vfatlib/vfatlib.c
@@ -428,6 +428,14 @@ VfatChkdsk(IN PUNICODE_STRING DriveRoot,
         /* No need to check FS */
         return (fs_close(FALSE) == 0 ? STATUS_SUCCESS : STATUS_DISK_CORRUPT_ERROR);
     }
+    else if (CheckOnlyIfDirty && fs_isdirty())
+    {
+        if (!(FsCheckFlags & FSCHECK_READ_WRITE) && !(FsCheckFlags & FSCHECK_INTERACTIVE))
+        {
+            fs_close(FALSE);
+            return STATUS_DISK_CORRUPT_ERROR;
+        }
+    }
 
     read_boot(&fs);