> For the complete documentation index, see [llms.txt](https://docs.flatredball.com/gum/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.flatredball.com/gum/code/files-and-fonts/troubleshooting.md). # Troubleshooting ## Introduction This page provides troubleshooting steps you can perform when content is not loading properly. ## Delete Bin/Obj By default, Gum projects copy content to the bin folder if the content is newer in source. If a file somehow becomes newer (such as by copy/pate, or reverting) in the bin folder, then the source fill will not get copied over. You can delete bin/obj folders and re-build your project to verify that content is loading correctly. Alternatively you can try loading the .gumj file that is in the bin folder to see if it visually matches the content in source. ## Debugger Breaks on FileNotFoundException for GumCommon.XmlSerializers When you call `GumUI.Initialize` with an XML project (`.gumx`), the debugger may stop with a `System.IO.FileNotFoundException` saying it could not load `GumCommon.XmlSerializers`. Your project is not broken, and you do not need to add that file. .NET's `XmlSerializer` first looks for a pre-generated serializer assembly named `.XmlSerializers.dll`. Gum does not ship one, so the lookup fails, .NET catches the exception itself, and it generates the serializer at runtime instead. The exception only appears because the debugger is set to break when it is thrown. To get past it, press **Continue** (F5). To stop it from appearing, uncheck **Break when this exception type is thrown** in the exception popup. If the project still does not load after you continue, the problem is a different exception. Check the next one the debugger reports. ## Clearing Browser Cache (Web) On web targets (KNI BlazorGL and other WebAssembly hosts), the browser may serve a cached copy of your `.gumj` project and its files. If your content looks out of date even though the source has changed, the browser cache is a likely culprit. Performing a hard refresh or clearing the browser cache makes sure you are loading the current `.gumj` file rather than a stale cached version. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.flatredball.com/gum/code/files-and-fonts/troubleshooting.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.