The result file uses logging which logs more than 700 000 entries in the log which makes it huge (about 111 MB) Such a large text file is quite hard to be serialized so that is why the exception you are getting.
As a workaround you may try exporting the result in HTML and review it. More information about the export you can find in this article:

http://docs.telerik.com/teststudio/getting-started/test-results/export-test-results

Thank you for your understanding.