I’ve tried duplicating 2 of my chats and it didn’t really work.
I needed to continue using the old chat because fixing the errors got me nowhere.
I also saw a few other people having the same issues. So I was wondering if there is an official best practice by now to duplicate the chat and then getting through the error messages/to a state that someone can actually work with?
Hey, Tom!
Can you share a chat URL with us? What error messages are you seeing?
Duplicating the chat so it doesn’t get too long is usually what we recommend. 
The duplicating part itself works
When I want to deploy (without any changes) this is the error message I get
11:07:03.962 Running build in Washington, D.C., USA (East) – iad1
11:07:03.962 Build machine configuration: 4 cores, 8 GB
11:07:04.107 Retrieving list of deployment files…
11:07:04.575 Downloading 147 deployment files…
11:07:05.423 Skipping build cache since Package Manager changed from “bun” to “npm”
11:07:05.579 Running “vercel build”
11:07:06.141 Vercel CLI 51.6.1
11:07:07.070 Installing dependencies…
11:07:12.514 npm error code ERESOLVE
11:07:12.515 npm error ERESOLVE unable to resolve dependency tree
11:07:12.515 npm error
11:07:12.515 npm error While resolving: my-v0-project@0.1.0
11:07:12.515 npm error Found: react@19.2.5
11:07:12.515 npm error node_modules/react
11:07:12.515 npm error react@“^19” from the root project
11:07:12.515 npm error
11:07:12.515 npm error Could not resolve dependency:
11:07:12.515 npm error peer react@“^16.8 || ^17.0 || ^18.0” from vaul@0.9.9
11:07:12.516 npm error node_modules/vaul
11:07:12.516 npm error vaul@“^0.9.6” from the root project
11:07:12.516 npm error
11:07:12.516 npm error Fix the upstream dependency conflict, or retry
11:07:12.516 npm error this command with --force or --legacy-peer-deps
11:07:12.516 npm error to accept an incorrect (and potentially broken) dependency resolution.
11:07:12.516 npm error
11:07:12.516 npm error
11:07:12.516 npm error For a full report see:
11:07:12.516 npm error /vercel/.npm/_logs/2026-04-21T09_07_07_251Z-eresolve-report.txt
11:07:12.516 npm error A complete log of this run can be found in: /vercel/.npm/_logs/2026-04-21T09_07_07_251Z-debug-0.log
11:07:12.549 Error: Command “npm install” exited with 1
This is the chat URL: https://v0.app/chat/urban-friends-home-page-live-2-LBcmJNsf0Jn
From the error logs, it looks like the problem are the following:
vaul package (version 0.9.9) only supports React 16.8, 17, or 18.Could you prompt v0 with the following?
You need to upgrade `vaul` to a version that supports React 19. Upgrade vaul to the latest version. Then regenerate the lockfile.
A lockfile is a record of the exact versions of all dependencies your project installed.
Without a lockfile:
vaul@^1.1.2, npm could install 1.1.2, 1.2.0, 1.5.0, etc. (any version matching ^1.1.2)With a lockfile:
vaul@1.1.2 specifically)In your case:
Your local package.json says vaul@^1.1.2 (latest), but your lockfile probably still had vaul@0.9.9 (old version). So Vercel was deploying the outdated version, causing the React 19 error. By regenerating the lockfile, it’ll record the correct version and Vercel will deploy it properly.
The prompt worked.
I got some error messages in the chat:
The script executor doesn’t support execSync for spawning shell commands. The lockfile regeneration can’t be done directly via the script runner.
However, the good news is that the auto-installer in this environment handles pnpm install automatically at the end of each turn when it detects package.json changes. Since I’ve already updated vaul to ^1.1.2 in package.json, the lockfile will be regenerated automatically when dependencies are resolved at the end of this turn.
The package.json has been updated with "vaul": "^1.1.2" which supports React 19. The pnpm lockfile will be automatically regenerated by the environment’s dependency resolver at the end of this response — no manual intervention needed.
but the deployment worked, which is the main part. And it seems like nothing is broken.
Glad to hear that worked for ya!
For the future, this is a good post to refer back to whenever you see build errors:
@pawlean I’m sorry to come back to this chat. For 4 of my 5 projects duplicating the chat seems to work fine.
For my biggest project which is also quite complex, at first it seemed to work fine (I could deploy it without a problem) but something is different to the previous version. User complained that they could not open one of the personalized links I’m sending them (just a spinning wheel/loading state).
When I redeployed the old version everything seemed to be working just fine again.
I’m not sure how to proceed here, because I would like to work in the code for small copy changes (and I’m on version 176), but when functionality breaks and I don’t understand why, I can’t really use it.
This is the old chat that works: https://v0.app/chat/mvp-march-v2-bnzHe05Ydj9
The is the new one: https://v0.app/chat/mvp-march-v2-2-G75JoF2wiZK
@pawlean did you see my previous message?
Do you see any errors in the browser console or runtime logs?
No I didn’t see any obvious errors there. I actually moved on quite a lot now with my project as it is in production.
I just don’t know how to continue, because it seems like something is breaking when I duplicate it.
You could download the code and upload it to a new chat with completely fresh context. That’s a option I’ve seen work in the past for context/history related issues
@amyegan I have tried down and uploading and it completely failed.
I feel stuck with this project as I have no idea what it is breaking and what not. Is there any chance to see what changed when duplicating?