Hi, Sohoil. Thought I would recount to you the behaviour of my system in this respect. If I build my program using a Multilock version of the File System library. And #define FS_OS_LOCKING as 0 in the file ‘FS_Conf.h’. I see a value of 2 passed into the function FS_X_OS_Init through the argument NumLocks. If I change the #define to equate FS_OS_LOCKING to 2. I still see a value of 2 passed into the function FS_X_OS_Init through the argument NumLocks. Sorry I cannot be of more help. Regards Tobe…