--- title: ASP.NET Core on IIS Express - Empty error starting... description: A troubleshooting walkthrough for an empty, unhelpful error when launching ASP.NET Core apps in IIS Express via Visual Studio or Rider. The root cause: the... canonical: https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: ASP.NET Core on IIS Express - Empty error starting application | daily.dev og:description: A troubleshooting walkthrough for an empty, unhelpful error when launching ASP.NET Core apps in IIS Express via Visual Studio or Rider. The root cause: the... og:url: https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt og:image: https://api.daily.dev/og/posts/IICvlVbPT.png og:image:alt: ASP.NET Core on IIS Express - Empty error starting application og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # ASP.NET Core on IIS Express - Empty error starting application **[Maarten Balliauw](https://daily.dev/sources/maartenballiauw)** · 4 min read · 0 upvotes · 0 comments ## Summary A troubleshooting walkthrough for an empty, unhelpful error when launching ASP.NET Core apps in IIS Express via Visual Studio or Rider. The root cause: the applicationhost.config template installed by IIS Express does not get updated with the ASP.NET Core Module entries even after installing the .NET Core hosting bundle, so projects copying from that template lack IIS hosting support. The fix involves manually adding the AspNetCoreModule and AspNetCoreModuleV2 global module registrations, the aspNetCore section, and module entries to the template config file, then deleting the generated .vs or .idea applicationhost.config so it regenerates correctly. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Why does IIS Express show a blank 'Error:' message with no details when starting an ASP.NET Core project? The applicationhost.config template that IIS Express copies for new projects lacks the ASP.NET Core Module entries, even if the .NET Core hosting bundle is installed. The hosting bundle installs the aspnetcore.dll binaries but does not update IIS Express's template config at %PROGRAMFILES(x86)%\IIS Express\config\templates\PersonalWebServer\applicationhost.config, so any project copying from it silently fails to host .NET Core. _Developers debugging silent IIS Express failures can save working fixes like this one on daily.dev._ ### How do I manually add ASP.NET Core Module support to IIS Express's applicationhost.config? Add three entries to the config file: under globalModules add AspNetCoreModule and AspNetCoreModuleV2 pointing to aspnetcore.dll and Asp.Net Core Module\V2\aspnetcorev2.dll; under the system.webServer sectionGroup add a section named aspNetCore with overrideModeDefault Allow; and under the empty location path's modules add lockItem entries for both module names. Then delete the generated .vs or .idea config and retry. _Developers configuring ASP.NET Core hosting on IIS Express can reference solutions like this on daily.dev._ ## Similar posts on daily.dev - [How to Upgrade ASP.NET MVC to .NET Step by Step](https://daily.dev/posts/how-to-upgrade-asp-net-mvc-to-net-step-by-step-i3p1uesfs) · C\# Corner · 2 upvotes · 0 comments - [The .NET Tools Blog](https://daily.dev/posts/the-net-tools-blog-tdsv0g0uj) · JetBrains · 6 upvotes · 0 comments - [How to Migrate from ASP.NET Framework to ASP.NET Core](https://daily.dev/posts/how-to-migrate-from-asp-net-framework-to-asp-net-core-e22ntd3va) · freeCodeCamp · 4 upvotes · 0 comments - [Fixing the "Newer version of Aspire.Hosting.AppHost required" error](https://daily.dev/posts/fixing-the-newer-version-of-aspire-hosting-apphost-required-error-vp8wk2gka) · The Art of Simplicity · 0 upvotes · 0 comments --- Tags: [#windows](https://daily.dev/tags/windows), [#.net](https://daily.dev/tags/.net), [#visual-studio](https://daily.dev/tags/visual-studio), [#aspnet](https://daily.dev/tags/aspnet) [View this post on daily.dev](https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"ASP.NET Core on IIS Express - Empty error starting application","url":"https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt"},"datePublished":"2026-10-04T13:04:10.879Z","dateModified":"2026-10-04T13:05:05.015Z","description":"A troubleshooting walkthrough for an empty, unhelpful error when launching ASP.NET Core apps in IIS Express via Visual Studio or Rider. The root cause: the...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/4900bcb886bde9993e0cb17466241860?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/4900bcb886bde9993e0cb17466241860?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Maarten Balliauw","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Maarten Balliauw","logo":"https://media.daily.dev/image/upload/s--rOTg3VYO--/f_auto,q_auto/v1791119043/logos/maartenballiauw?_a=BAMAMicg0","url":"https://daily.dev/sources/maartenballiauw"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"windows,.net,visual-studio,aspnet","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Maarten Balliauw","item":"https://daily.dev/sources/maartenballiauw"},{"@type":"ListItem","position":3,"name":"ASP.NET Core on IIS Express - Empty error starting application"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/asp-net-core-on-iis-express---empty-error-starting-application-iicvlvbpt#faq","mainEntity":[{"@type":"Question","name":"Why does IIS Express show a blank 'Error:' message with no details when starting an ASP.NET Core project?","acceptedAnswer":{"@type":"Answer","text":"The applicationhost.config template that IIS Express copies for new projects lacks the ASP.NET Core Module entries, even if the .NET Core hosting bundle is installed. The hosting bundle installs the aspnetcore.dll binaries but does not update IIS Express's template config at %PROGRAMFILES(x86)%\\IIS Express\\config\\templates\\PersonalWebServer\\applicationhost.config, so any project copying from it silently fails to host .NET Core. Developers debugging silent IIS Express failures can save working fixes like this one on daily.dev."}},{"@type":"Question","name":"How do I manually add ASP.NET Core Module support to IIS Express's applicationhost.config?","acceptedAnswer":{"@type":"Answer","text":"Add three entries to the config file: under globalModules add AspNetCoreModule and AspNetCoreModuleV2 pointing to aspnetcore.dll and Asp.Net Core Module\\V2\\aspnetcorev2.dll; under the system.webServer sectionGroup add a section named aspNetCore with overrideModeDefault Allow; and under the empty location path's modules add lockItem entries for both module names. Then delete the generated .vs or .idea config and retry. Developers configuring ASP.NET Core hosting on IIS Express can reference solutions like this on daily.dev."}}]} ```