A quick note on a common confusion: When a Switch NSP fails to install, 90% of Google results scream "Update your sigpatches!" This is a sigpatch error.
This is the most frequent cause. If a download is interrupted or the source file is corrupted, the Program NCA (usually the largest file) might be missing or truncated. 2. Update/DLC vs. Base Game the nsp file is missing a program-type nca
Why does this happen? Is the file corrupt? Is your SD card dying? Do you need a new "sigpatch"? A quick note on a common confusion: When