diff --git a/openhtf/output/proto/mfg_event_converter.py b/openhtf/output/proto/mfg_event_converter.py
index dbf3ac1b1..25a8b941b 100644
--- a/openhtf/output/proto/mfg_event_converter.py
+++ b/openhtf/output/proto/mfg_event_converter.py
@@ -64,7 +64,7 @@
 }
 
 _GIBI_BYTE_TO_BASE = 1 << 30
-MAX_TOTAL_ATTACHMENT_BYTES = int(1.9 * _GIBI_BYTE_TO_BASE)
+MAX_TOTAL_ATTACHMENT_BYTES = int(0.9 * _GIBI_BYTE_TO_BASE)
 
 _LOGGER = logging.getLogger(__name__)