diff --git a/src/servers/model/preprocess/master.ts b/src/servers/model/preprocess/master.ts
index 365d6f3fa496a60dc1f6c88e9cf3d1221917151e..9ff8b8e1fbb321579029f40963ae563aba7f502a 100644
--- a/src/servers/model/preprocess/master.ts
+++ b/src/servers/model/preprocess/master.ts
@@ -51,7 +51,7 @@ if (Object.keys(cmdArgs).filter(k => (cmdArgs as any)[k] !== null).length === 0
 }
 
 let entries: PreprocessEntry[] = []
-let config: PreprocessConfig = { numProcesses: 1, customProperties: void 0 }
+let config: PreprocessConfig = { numProcesses: cmdArgs.folderIn ? +(cmdArgs.folderNumProcesses || 1) : 1, customProperties: void 0 }
 
 if (cmdArgs.input) entries.push({ source: cmdArgs.input, cif: cmdArgs.outCIF, bcif: cmdArgs.outBCIF });
 // else if (cmdArgs.bulk) runBulk(cmdArgs.bulk);