diff --git a/server/glz-encoder.c b/server/glz-encoder.c
index c258726c..dba2cd12 100644
--- a/server/glz-encoder.c
+++ b/server/glz-encoder.c
@@ -84,7 +84,7 @@ static inline void encode_32(Encoder *encoder, unsigned int word)
 static inline void encode_64(Encoder *encoder, uint64_t word)
 {
     encode_32(encoder, (uint32_t)(word >> 32));
-    encode_32(encoder, (uint32_t)(word & 0xffffff));
+    encode_32(encoder, (uint32_t)(word & 0xffffffffu));
 }
 
 static inline void encode_copy_count(Encoder *encoder, uint8_t copy_count)