>I was able to resolve the issue by streaming the entire content into the file. So, a 223 MB .xls file can then be created.

Can you post the code that solved your problem? I was going to suggest something along those lines, but didn't get far because, with the encoding you were doing with the StreamWriter, I didn't find an applicable overload with the FileStream ... and, unfortunately, I didn't have the time to investigate it further. Others might benefit from your solution.

~~Bonnie