Here in above data file string 3 is 11.2 and string 4 is 16.43. same way in full file in need to replace the value of string 4 to string 3 and a option of + or - thr value of text 1.text.
please explain better, what should string 3 now be, and what is the criteria for the option of + or - and detail what the output line should look like with example including content of text1

.maxfilesize does not do what you expected, it is for the size of the filenames returned, when multiple files are selected not the space of the file on the disk, max value 32k, default 256

If the data file ismore than 2 mb error shows
at which line does the error occur?
the size of the saved file is not affected by any thing from the common dialog
i was able to write files in excess of 32gb using similar code, takes a while though