diff --git a/.gitignore b/.gitignore
index b1329144..1d83e7a5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -65,3 +65,5 @@ address_cache
 /_build/*
 CMakeLists.txt.user
 /out/*
+Obj/
+Release/
diff --git a/src/bacnet/basic/object/bacfile.c b/src/bacnet/basic/object/bacfile.c
index 29e78d74..7dc8f32a 100644
--- a/src/bacnet/basic/object/bacfile.c
+++ b/src/bacnet/basic/object/bacfile.c
@@ -163,17 +163,21 @@ static long fsize(FILE *pFile)
     return (size);
 }
 
-unsigned bacfile_file_size(uint32_t object_instance)
+BACNET_UNSIGNED_INTEGER bacfile_file_size(uint32_t object_instance)
 {
     char *pFilename = NULL;
     FILE *pFile = NULL;
-    unsigned file_size = 0;
+    long file_position = 0;
+    BACNET_UNSIGNED_INTEGER file_size = 0;
 
     pFilename = bacfile_name(object_instance);
     if (pFilename) {
         pFile = fopen(pFilename, "rb");
         if (pFile) {
-            file_size = fsize(pFile);
+            file_position = fsize(pFile);
+            if (file_position >= 0) {
+                file_size = (BACNET_UNSIGNED_INTEGER)file_position;
+            }
             fclose(pFile);
         }
     }
diff --git a/src/bacnet/basic/object/bacfile.h b/src/bacnet/basic/object/bacfile.h
index 298a8f46..183b39d3 100644
--- a/src/bacnet/basic/object/bacfile.h
+++ b/src/bacnet/basic/object/bacfile.h
@@ -39,6 +39,7 @@
 #include "bacnet/bacnet_stack_exports.h"
 #include "bacnet/bacdef.h"
 #include "bacnet/bacenum.h"
+#include "bacnet/bacint.h"
 #include "bacnet/apdu.h"
 #include "bacnet/arf.h"
 #include "bacnet/awf.h"
@@ -108,7 +109,7 @@ extern "C" {
     void bacfile_init(
         void);
     BACNET_STACK_EXPORT
-    uint32_t bacfile_file_size(
+    BACNET_UNSIGNED_INTEGER bacfile_file_size(
         uint32_t instance);
 
     /* handling for read property service */