# Retool: React App Builder Sandbox Installs May Fail to Install Dependencies

- Provider: [Retool](https://outages.live/retool.md)
- Type: Incident
- State: Resolved
- Worst impact: Partial outage
- Started: 2026-08-20 17:26 UTC
- Resolved: 2026-08-20 23:20 UTC (lasted 5 h 54 min)
- Components: New app builder, Self Hosted On-Premise
- Official update: https://stspg.io/hfvc3zn0ct60

## Updates from Retool

### resolved, 2026-08-20 23:20 UTC

This incident is resolved. Images with the fix are out: 4.0.12-stable 4.43.0-edge Our minimum release age for React app builder dependencies is 5 days, so this incident will self-resolve for any self-hosted deployments that don't upgrade on August 24th, by 7am PST. All currently affected self-hosted versions: stable: 4.0.0 - 4.0.11 edge: 4.1, 4.9, 4.16, 4.19, 4.23, 4.27, 4.31, 4.35, 4.40

### monitoring, 2026-08-20 21:08 UTC

Images with the fix are out: 4.0.12-stable 4.43.0-edge Our minimum release age for React app builder dependencies is 5 days, so this incident will self-resolve for any self-hosted deployments that don't upgrade on August 24th, by 7am PST. All currently affected self-hosted versions: stable: 4.0.0 - 4.0.11 edge: 4.1, 4.9, 4.16, 4.19, 4.23, 4.27, 4.31, 4.35, 4.40

### identified, 2026-08-20 18:16 UTC

This issue affects Retool version 4.0.0+ (stable and edge), specifically for 1) newly-created React apps, 2) new publishes of existing React apps, and 3) cold starts of sandboxes when editing existing React apps. Existing published apps that do not get published after August 19th are unaffected. Self-hosted customers can update to 4.43.0-edge to get an immediate fix. A patch to our stable release channel is coming soon.

### identified, 2026-08-20 17:30 UTC

This issue no longer affects the React App Builder on Retool Cloud. We have identified the issue for self-hosted, and are working on releasing images with a fix

### investigating, 2026-08-20 17:26 UTC

Retool's app builder may fail to install and connect to a sandbox due to downstream dependency issues. This affects both Cloud and Self-Hosted Retool instances.