diff --git a/CPP/7zip/UI/Common/CompressCall.cpp b/CPP/7zip/UI/Common/CompressCall.cpp
index 0f875365..02c3dff9 100644
--- a/CPP/7zip/UI/Common/CompressCall.cpp
+++ b/CPP/7zip/UI/Common/CompressCall.cpp
@@ -257,7 +257,7 @@ HRESULT CompressFiles(
       if (fo.BlockLogSize)
       {
         params += " -ms=";
-        ConvertUInt32ToString(1 << fo.BlockLogSize, temp);
+        ConvertUInt64ToString(1ULL << fo.BlockLogSize, temp);
         params += temp;
         params += "b";
       }