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React App Builder Sandbox Installs May Fail to Install Dependencies

Major Impact Resolved Duration: 5h 53m August 20, 2026

Incident Lifecycle

Investigating Identified Identified Monitoring
Affected Components
New app builder Self Hosted On-Premise

Incident Timeline

Monitoring
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
Aug 20, 2026 at 9:08 PM UTC
Identified
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.
Aug 20, 2026 at 6:16 PM UTC
Identified
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
Aug 20, 2026 at 5:30 PM UTC
Investigating
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.
Aug 20, 2026 at 5:26 PM UTC
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