Quarto Preview fails to load

[bensoltoff]

System details:

Positron and OS details:

Positron Version: 2025.08.0 build 130
Code - OSS Version: 1.102.0
Commit: 76ddce5
Date: 2025-08-01T20:08:51.894Z
Electron: 35.6.0
Chromium: 134.0.6998.205
Node.js: 22.15.1
V8: 13.4.114.21-electron.0
OS: Darwin arm64 24.6.0

Session details:

R 4.5.1
Quarto 1.7.33

Describe the issue:

I have sporadic issues getting the Quarto: Preview feature to work. In some workspaces it works fine, but in one workspace I cannot get it to work. I've been trying to pin down a reproducible example but it seems specific to this one workspace (it's a private Git repo which I cannot share publicly). The workspace is also a Quarto Project with a _quarto.yml file.

Steps to reproduce the issue:

1. Create a blank Quarto document in the workspace. I used

---
title: "Untitled"
format: html
---

2. Attempt to preview the document (from the command palette "Quarto: Preview").

Expected or desired behavior:

Generate a live preview of the document.

Were there any error messages in the UI, Output panel, or Developer Tools console?

The terminal produces this output:

bcs88@COECIS-HJGTG2FW6P assessments % quarto preview /Users/bcs88/Projects/info-5001/assessments/test.qmd --no-browser --no-watc
h-inputs --output-dir /var/folders/y5/0kt9x9qd2f13mtkqx3w0lh9r0000gr/T/tmp-90099-HMq5LbGjatkR --embed-resources
ERROR: NotFound: No such file or directory (os error 2): stat '/Users/bcs88/Projects/info-5001/assessments/.quarto/quarto-session-temp224ca9296dcceba6'

Stack trace:
    at Object.statSync (ext:deno_fs/30_fs.js:425:3)
    at createWalkEntrySync (file:///Applications/quarto/bin/quarto.js:2028:23)
    at walkSync (file:///Applications/quarto/bin/quarto.js:2134:15)
    at walkSync.next (<anonymous>)
    at advanceMatch (file:///Applications/quarto/bin/quarto.js:2257:20)
    at advanceMatch.next (<anonymous>)
    at expandGlobSync (file:///Applications/quarto/bin/quarto.js:2273:24)
    at expandGlobSync.next (<anonymous>)
    at expandGlobs (file:///Applications/quarto/bin/quarto.js:5114:24)
    at resolveGlobs (file:///Applications/quarto/bin/quarto.js:5192:26)

I checked the .quarto folder and a quarto-session-temp* folder has been generated, but it has a different hash value. If I attempt to run the same shell command from the Terminal app outside of Positron it works correctly.

[juliasilge]

Gosh, that sounds pretty wild! 👀 I don't have any ideas off the top of my head for what might be going on, but we can keep an eye out for other reports.

• I don't suppose you could open up VS Code in that same workspace and see if the command works correctly from VS Code?
• Can you share exactly what version of the Quarto extension you have when you are observing this?

We may end up having you open up a discussion with this info at https://github.com/quarto-dev/quarto-cli/discussions. I am not sure if this problem is arising from the Quarto CLI, the Quarto VS Code extension, or maybe Positron possibly.

[bensoltoff]

Yes, it works from VSCode with the Quarto extension installed. I have version 1.124.0 installed for the Quarto extension.

[bensoltoff]

Since it's a Git repo I tried cloning another local copy and previewing it in that location. Still doesn't work, but now it doesn't work in a different way.

quarto preview /Users/bcs88/Desktop/assessments/test.qmd --no-browser --no-watch-inputs --o
utput-dir /var/folders/y5/0kt9x9qd2f13mtkqx3w0lh9r0000gr/T/tmp-12674-jIa5A3cXYaaH --embed-resources
pandoc --embed-resources
  to: html
  output-file: test.html
  standalone: true
  section-divs: true
  html-math-method: mathjax
  wrap: none
  default-image-extension: png
  toc: true
  variables: {}
  
metadata
  document-css: false
  link-citations: true
  lang: en
  date-format: long
  date-modified: last-modified
  code-annotations: hover
  code-copy: true
  lightbox: true
  title: Untitled
  
Output created: ../../../../var/folders/y5/0kt9x9qd2f13mtkqx3w0lh9r0000gr/T/tmp-12674-jIa5A3cXYaaH/test.html

Watching files for changes
Browse at http://localhost:5418/../../../../../var/folders/y5/0kt9x9qd2f13mtkqx3w0lh9r0000gr/T/tmp-12674-jIa5A3cXYaaH/test.html
GET: /var/folders/y5/0kt9x9qd2f13mtkqx3w0lh9r0000gr/T/tmp-12674-jIa5A3cXYaaH/test.html (404: Not Found)

[juliasilge]

Thanks for checking with VS Code!

• Is the repo public so that we might be able to try it out ourselves? If not, could you create a similar project that demonstrates the problem?
• Do you think you might be running more than one quarto preview at a time? Like a process somewhere is running quarto preview, and then you are running quarto preview again separately? Folks run into problems sometimes in such circumstances.

[bensoltoff]

Unfortunately it's not public and I can't easily change that. I also had the issue pop up in another repo but I think it has to be something specific to my machine. When I cloned the same repos using Positron on Posit Workbench the preview worked fine.

[bensoltoff]

And as far as I could tell it was the only running quarto preview process. I closed all other Positron and RStudio sessions.

[juliasilge]

OK, would you feel OK if we closed this issue for now, until we have a reproducible example that generates the problem? Definitely feel free to open a new one or chime in here again if you have something shareable! We would love to get to the bottom of this.