Hello. I'm the developer of the autosplitter for TMNF/TMUF and I wanted to address the last comment by Argide.

The autosplitter, just like any other autospliter for LiveSplit is a text file, meaning it isn't any executable code that runs by itself. This makes it almost impossible for the autosplitter to be detected as a "virus", because it's just text. Please check which file is actually deemed malicious as it's more likely that the LiveSplit program itself is detected by your antivirus, and not the autosplitter.