diff --git a/speeduino/SD_logger.cpp b/speeduino/SD_logger.cpp
index c98b4766..0d3b1573 100644
--- a/speeduino/SD_logger.cpp
+++ b/speeduino/SD_logger.cpp
@@ -330,7 +330,9 @@ bool createLogFile()
   currentLogFileNumber = getNextSDLogFileNumber();
 
   //Create the filename
-  sprintf(filenameBuffer, "%s%04d.%s", LOG_FILE_PREFIX, currentLogFileNumber, LOG_FILE_EXTENSION);
+  //sprintf(filenameBuffer, "%s%04d.%s", LOG_FILE_PREFIX, currentLogFileNumber, LOG_FILE_EXTENSION);
+  if(currentLogFileNumber > MAX_LOG_FILES) { currentLogFileNumber = 1; } //If we've run out of file numbers, start again from 1
+  snprintf(filenameBuffer, 13, "%s%04d.%s", LOG_FILE_PREFIX, currentLogFileNumber, LOG_FILE_EXTENSION);
 
   logFile.close();
   if (logFile.open(filenameBuffer, O_RDWR | O_CREAT | O_TRUNC)) 
@@ -364,7 +366,8 @@ bool getSDLogFileDetails(uint8_t* buffer, uint16_t logNumber)
   if(logFile.isOpen()) { endSDLogging(); }
 
   char filenameBuffer[13]; //8 + 1 + 3 + 1
-  sprintf(filenameBuffer, "%s%04d.%s", LOG_FILE_PREFIX, logNumber, LOG_FILE_EXTENSION);
+  if(logNumber > MAX_LOG_FILES) { logNumber = MAX_LOG_FILES; } //If we've run out of file numbers, start again from 1
+  snprintf(filenameBuffer, 13, "%s%04d.%s", LOG_FILE_PREFIX, logNumber, LOG_FILE_EXTENSION);
   
   if(sd.exists(filenameBuffer))
   {
diff --git a/speeduino/SD_logger.h b/speeduino/SD_logger.h
index 13bb353b..59a78570 100644
--- a/speeduino/SD_logger.h
+++ b/speeduino/SD_logger.h
@@ -49,7 +49,7 @@
 
 //Test values only
 #define SD_LOG_FILE_SIZE  10000000 //Default 10mb file size
-#define MAX_LOG_FILES     10000
+#define MAX_LOG_FILES     9999
 #define LOG_FILE_PREFIX "SPD_"
 #define LOG_FILE_EXTENSION "csv"
 #define RING_BUF_CAPACITY (SD_LOG_ENTRY_SIZE * 10) //Allow for 10 entries in the ringbuffer. Will need tuning