diff --git a/src/main/java/org/radarbase/output/source/AzureSourceStorage.kt b/src/main/java/org/radarbase/output/source/AzureSourceStorage.kt
index ae86d0e..de94e25 100644
--- a/src/main/java/org/radarbase/output/source/AzureSourceStorage.kt
+++ b/src/main/java/org/radarbase/output/source/AzureSourceStorage.kt
@@ -24,6 +24,7 @@ class AzureSourceStorage(
 
     private fun blobClient(path: Path) = blobContainerClient.getBlobClient(path.toKey())
 
+    ///
     override suspend fun list(path: Path, maxKeys: Int?): List<SimpleFileStatus> =
         withContext(Dispatchers.IO) {
             var iterable: Iterable<BlobItem> = blobContainerClient.listBlobsByHierarchy("$path/")
@@ -34,7 +35,7 @@ class AzureSourceStorage(
                 SimpleFileStatus(
                     Paths.get(it.name),
                     it.isPrefix ?: false,
-                    it.properties?.lastModified?.toInstant(),
+                    if (it.isPrefix) null else it.properties?.lastModified?.toInstant(),
                 )
             }
         }