Liquid syntax error : Unknown tag 'schema' when running shopify app dev

[Harry_Pagefly]

I have reproduced the issue on the latest CLI version.

Yes, I am on the latest version

I have searched existing posts and this report is not a duplicate.

Yes, this isn’t a duplicate

In which of these areas are you experiencing a problem?

App

Expected behavior

Able to run the app

Actual behavior

Throw error in app-preview stage:
[blocks/app-embed.liquid] Liquid syntax error (line 132): Unknown tag ‘schema’

Reproduction steps

Your app need to have embed app block. Then run shopify app dev

Verbose output

09:14:44 │               app-preview │ ❌ Error
09:14:44 │      pagefly-theme-helper │ └  [blocks/app-embed.liquid] Liquid syntax error (line 132): Unknown tag 'schema'

Operating system

Mac OS

CLI version

3.87.0

Shell

zsh

Nodejs version

v24.11.1

What language and version are you using in your application?

Node

[Harry_Pagefly]

FYI, it still works normally 2-3 hours ago. But suddenly failed when i re-run the app again

[sunny_kaiwar]

encountered the same issue! the app was working fine yesterday, and won’t work today without any code change or package upgrade

[user108]

Version 3.84.2 encountered the same problem.

[steven_pagefly]

Got this issue too struggling to use the trick to bypass

[Harry_Pagefly]

@KyleG-Shopify we have this critical issue, any updates from your end?

[Harry_Pagefly]

Currently we need by pass the app_preview check by remove the embed app block then run shopify app dev and finally reverse the removed embed app block

[Duy_Nguyen]

Same issue here, I am still managing to get the result but no hope. All things were good until last few hours. I tried to do the trick to run without any theme app blocks and then paste it back but it didn’t work. Hope to see the hot-fix soon

[Pemond]

@Liam-Shopify can confirm this issue with shopify cli version 3.84.1

[azy]

same issue with cli version 3.88.1.

[james_collins]

I’m also seeing this issue occur, it wasn’t a problem earlier today but is now.

I can build, but I can’t dev or deploy our existing app.

Updating to the latest shopify cli version didn’t help either.

[Zun]

Same issue, I just init new app react router and create a new theme extensions, but can’t deploy

[OpusAppDev]

Same issue , stuck when trying deploy theme extension

s

Liquid syntax error (line 32): Unknown tag ‘schema’

[navdeep]

yep marking my attendance here for the same issue

[sunnysek2019]

same issue with cli version 3.88.1.

[mehdi7]

Same issue…watching this thread

[Chi_n_Nguy_n_Van]

Same issue with cli version 3.84.2

[James_Wilson]

Also getting this issue, working fine 2 hours ago. Spoke to their support who didn’t understand the issue.

Getting the issues on both version 3.84.1 and after upgrading to 3.88.1

[simon_b]

Also experiencing this issue, I tried disabling some checks in the .theme-check.yml file but no luck

EDIT - Can’t deploy or run the dev server as a result of this issue.

[Digital_Crafts]

also experiencing this issue. It was working well a couple of hours ago.