Writing a binary fikle using C#

Question

I'm writing a binary file using C#.

My algorithm, etc are all correct and I have validated using witing of small binary files (when I say amall, I mean of sized 200 to 300 MB)

 

but when my files size becomes as larghe as 2GB (I want to write a file of size 6GB), the process goes on endlessly.

 

Any clues, what might be happening? 

 

 Thanks a lot.