diff --git a/sources/Service/InterfaceDiscovery/InterfaceDiscovery.php b/sources/Service/InterfaceDiscovery/InterfaceDiscovery.php
index 67a5ca2fa..95fec0f43 100644
--- a/sources/Service/InterfaceDiscovery/InterfaceDiscovery.php
+++ b/sources/Service/InterfaceDiscovery/InterfaceDiscovery.php
@@ -178,6 +178,13 @@ class InterfaceDiscovery
 					continue;
 				}
 				$aTmpClassMap = include $sAutoloadFile;
+				if (! is_array($aTmpClassMap)) {
+					//can happen when setup compilation broken in the middle
+					//ex: $sAutoloadFile could be empty and $aTmpClassMap is a int
+					$aAutoloaderErrors[] = $sAutoloadFile;
+					continue;
+				}
+
 				/** @noinspection SlowArrayOperationsInLoopInspection we are getting an associative array so the documented workarounds cannot be used */
 				$aClassMap = array_merge($aClassMap, $aTmpClassMap);
 			}