My original Retool React App Builder app is frozen at “Starting preview server”

💬 App Building
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  1. My original Retool React App Builder app is frozen at “Starting preview server” and the editor becomes unusable. The published app still works, but it is significantly older than my current unpublished work, so I cannot restore to the published version.

    The problem began after a long-running builder/import session. The app now shows behavior consistent with stranded unpublished working-tree changes.

    Please do not revert or reset the app to the last published version. I need the current unpublished working tree recovered and committed to its existing branch/thread so I can continue from the latest state.

    The old published production app and database are currently functioning normally.

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Summary

On a Cloud instance using the new React app builder with Retool-managed source control, an app is frozen at "Starting preview server" and the editor is unusable; the published version still works but is older, and the goal is to recover the stranded unpublished working-tree changes rather than revert to the published state.

AI Response

This matches a known pattern where the new app builder's in-editor sandbox gets stuck (e.g., preview server / 'Integrate changes' failures traced by staff to Vite port collisions in the sandbox, fixed in 4.17.0 and rolled out to Cloud around early July 2026), leaving the editing branch out of sync with a still-healthy published app. First try loading the app in a freshly initialized editor thread/tab and confirm the running version is up to date, since older threads can stay pinned to a stale state and keep re-triggering the broken preview. Be aware that on Retool-managed git there is no self-service hard-reset or local clone, and 'Reset branch' resets to a baseline snapshot rather than merging in changes, so it can make unpublished work appear as removals. In the corroborating reports, recovery was ultimately achieved by starting fresh from the last clean published version and re-applying outstanding work, so preservation of stranded unpublished changes is not guaranteed via a self-service path.

Sources

:bookmark: Editing branch stuck out of sync with published version — "integrate changes" fails, no way to reset (Retool-managed git)
A directly comparable new-app-builder + Retool-managed-git report where the editing branch was stuck out of sync with the published version; staff attributed the integrate/preview failures to a sandbox Vite port-collision bug (fixed in 4.17.0), and the reporter recovered by starting fresh from the last publish and rebuilding subsequent work.
:bookmark: Reset branch to merge changes from main
A solved topic explaining why 'Reset branch' leaves a branch looking out of sync (it resets to a baseline snapshot rather than applying merged changes) and recommending recreating the branch from main instead of committing the phantom removal diffs.

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