While it looks like a crash, it is almost always a normal part of how the Unreal Engine—which the Mod Kit is built on—operates. Below are the primary reasons this happens and how you can fix it. 1. The Main Reason: Shader Compilation

This forces the launcher to discard the corrupted partial file and redownload the specific chunk causing the blockage.

: Ensure your computer meets the game's system requirements and that your graphics drivers are up to date.

The "Hello Neighbor Mod Kit stuck at 45%" error is a common problem reported by users on various online forums, including Reddit, Steam, and the game's official support channels. The issue seems to occur randomly, and users have reported experiencing it on different platforms, including Windows, macOS, and Linux.