not able to update memory content (.mif files) using 'update memory initialization' !

Hi

I am using Quartus v12.1. I have read in many relevant threads that following steps can be taken to update .mif file content.

1. change .mif file(s)

2. select Update Memory Initialization File in Quartus processing menu

3. run the assembly step

But in my fpga memory content is not updated using above steps. Is this bacause of different version? Any suggestion is appreciated.