https://devzone.nordicsemi.com/f/nordic-q-a/72486/usbd_msc-example-about-f_lseek-usageHi, dear all: I’m trying to use usbd_msc example(nrf 52840 DK/sdk 17.0.2 ) and written a string A (8 bytes) into a .txt file； Now I want write the same file another string B at the end of A； And,I know I should use f_lseek(&amp;file, 8) to move theen-USTelligent Community 13Tue, 09 Mar 2021 01:50:05 GMThttps://devzone.nordicsemi.com/thread/298538?ContentTypeID=1Tue, 09 Mar 2021 01:50:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4c303e85-62e3-41e3-9add-e056706f0a96Chris_<p>Thanks a lot,！</p> <p>&nbsp; &nbsp; &nbsp;I do as your suggestion, It works as my expect when I set f_open(my_file, my_filename, FA_OPEN_ALWAYS | FA_WRITE | FA_OPEN_APPEND)，</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/298341?ContentTypeID=1Mon, 08 Mar 2021 11:36:22 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2d0eeacc-2d37-4373-b188-88fb024f9c00Dmitry<p>Hi,</p> <p>if you need to move pointer to the end of file, either open it with FA_OPEN_APPEND flag, or use very large offset (LONG_MAX, 0x7fffffff) in f_lseek.</p><div style="clear:both;"></div>