# Net new issues (delta) scan troubleshooting ## Problem **Net new issues scans fail to find issues on npm-based reference scans.** The net new issues filter in the IDEs compares the software Projects in two folders or two branches from a Git project.\ \ Some package managers, such as NuGet, pip, npm, and so on, require specific manifest files to be generated before you can perform a scan analysis. These files, for example, `package-lock.json` or `obj/project.assets.json` for NuGet, are typically generated by the Project's compiler or running a specific installation command. ## Solution Required manifest files must be generated before you can perform a scan analysis. These files, for example, `package-lock.json` or `obj/project.assets.json` for NuGet must have been generated on the current branch or folder and either: * Be committed to the reference branch before the scan * Be prepared (compiled) into a different directory, that will be used as a reference folder for Snyk scan