diff --git a/spinn_utilities/make_tools/file_converter.py b/spinn_utilities/make_tools/file_converter.py
index 36c98dff..33a5c178 100644
--- a/spinn_utilities/make_tools/file_converter.py
+++ b/spinn_utilities/make_tools/file_converter.py
@@ -21,7 +21,7 @@
 
 COMMA_SPLIITER = re.compile(r'(?!\B"[^"]*),(?![^"]*"\B)')
 STRING_REGEXP = re.compile(r'"([^"]|\\"|(""))*"')
-FORMAT_EXP = re.compile(r"(%+\d*(?:\.\d+)?[cdfiksuxRF])")
+FORMAT_EXP = re.compile(r"(%+\d*(?:\.\d+)?[cdfiksuxRFK])")
 LOG_END_REGEX = re.compile(r'\)(\s)*;')
 END_COMMENT_REGEX = re.compile(r"/*/")
 LOG_START_REGEX = re.compile(