System.IO.IOException on fresh ASP project
Hi everyone,
I'm trying to get started with ASP.NET and Rider on Linux. Having installed mono, msbuild and xsp, I was able to simply press “Run” in my newly created template project and watch a server start; however, on localhost:5000, I am greeted with an IOException. I don't even have any idea where to look for problems, so I'd appreciate some assistance here.
System info:
JetBrains Rider 2026.2.3.1
Build #RD-262.10968.170, built on September 30, 2026
Source revision: aace5c07ccc04
Runtime version: 25.0.4+1-b508.27 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Toolkit: sun.awt.X11.XToolkit
Linux 7.2.8-arch1-2
Arch Linux; glibc: 2.44; desktop: KDE (plasmashell 6.7.5)
Exception reporter ID: 290626362ab7bd8-c77b-476f-a38f-0851ce5c15d9
JCEF version: 144.0.15-262-b37
.NET Core v10.0.9 x64 (Server GC)
GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation
Memory: 2048MiB
Cores: 8
Registry:
external.system.auto.import.disabled=true
ide.experimental.ui=true
vfs.windows.use.buffered.directory.stream=false
trace.state.event.service.url=https://api.jetbrains.cloud/trace-status
Non-Bundled Plugins:
me.rafaelldi.aspire (2.8.1)
Current Desktop: KDEPlease sign in to leave a comment.
Hello WildRikku
Thank you for contacting us, and sorry to hear that you've run into this error on your first project.
Unfortunately, the exception name alone does not tell us what failed. Could you please share the following information:
- the full exception text and stack trace from the error page at `localhost:5000` (a screenshot of the page also works)
- the output in the Run tool window after you press Run
- the name of the template you chose when you created the project
- the Mono version (`mono --version`) and the XSP version
If the output is long, please upload it to https://uploads.jetbrains.com and share the Upload ID that the page shows after the upload. Only JetBrains staff can open the file, so the ID is safe to post in this thread.
Thank you in advance and have a great day!