diff --git a/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php b/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php
index b7a10ec3..2b0e9432 100644
--- a/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php
+++ b/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php
@@ -13,7 +13,6 @@
 use Boundwize\StructArmed\Cache\AnalysisResultCache;
 use Boundwize\StructArmed\Cache\CachePathFactory;
 use Boundwize\StructArmed\Progress\ProgressHandlerInterface;
-use FilesystemIterator;
 use RuntimeException;
 
 use function array_fill;
@@ -336,13 +335,11 @@ public function extract(
             }
         }
 
-        // when --no-cache is used and no files in the cache directory yet, remove dir cache
-        // as means only for temporary file for worker needs
+        // when --no-cache is used, the directory only held worker temporary files:
+        // remove it best-effort, rmdir() refuses a non-empty directory atomically,
+        // so a concurrent run's files or an existing cache keep it in place
         if (! $this->analysisResultCache instanceof AnalysisResultCache) {
-            $fileSystemIterator = new FilesystemIterator($cacheDirectory);
-            if (! $fileSystemIterator->valid()) {
-                rmdir($cacheDirectory);
-            }
+            @rmdir($cacheDirectory);
         }
 
         if ($failures !== []) {
diff --git a/src/Cache/AnalysisResultCache.php b/src/Cache/AnalysisResultCache.php
index dd15a30e..6578bd94 100644
--- a/src/Cache/AnalysisResultCache.php
+++ b/src/Cache/AnalysisResultCache.php
@@ -17,7 +17,6 @@
 use Boundwize\StructArmed\Composer\ComposerJsonProvider;
 use Boundwize\StructArmed\Rule\RuleViolation;
 use Boundwize\StructArmed\Rule\RuleViolationCollection;
-use FilesystemIterator;
 
 use function array_fill_keys;
 use function array_is_list;
@@ -177,11 +176,9 @@ public function clear(): void
             }
         }
 
-        // only remove the cache directory if it is empty
-        $fileSystemIterator = new FilesystemIterator($this->cacheDirectory);
-        if (! $fileSystemIterator->valid()) {
-            rmdir($this->cacheDirectory);
-        }
+        // only remove the cache directory if it is empty: rmdir() refuses a
+        // non-empty directory atomically, so a concurrent run's files keep it
+        @rmdir($this->cacheDirectory);
     }
 
     public function getCacheDirectory(): string