# An error occurred while executing Hermes command... Vega 0.21 & 0.22 **URL:** \ **Category:** Bug Reports\ **Created:** [February 3, 2026, 7:20pm UTC](https://community.amazondeveloper.com/t/an-error-occurred-while-executing-hermes-command-vega-0-21-0-22/27581 "2026-02-03T19:20:48Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Tony](https://avatars.discourse-cdn.com/v4/letter/t/ee7513/32.png) [@Tony](https://community.amazondeveloper.com/u/Tony)\ **Post date:** [February 3, 2026, 7:20pm UTC](https://community.amazondeveloper.com/t/an-error-occurred-while-executing-hermes-command-vega-0-21-0-22/27581/1 "2026-02-03T19:20:48Z")
[bug\_logs.txt](https://community.amazondeveloper.com/uploads/short-url/i1S1iBjIyM6826T3EBtj1yrEnhU.txt) (5.7 KB) # πŸ‘‰ Bug Description * * * ## 1. Summary _Provide a brief description of the bug in the SDK and its impact on app functionality._ ```auto When attempting to build our project we are seeing an error An error occurred while executing Hermes command /Users/[userName]/vega/sdk/0.22.5875/packages/VegaUIReact-Hermes/VegaUIReact-Hermes-0.72.x_vodka.219616.0/AL2_x86_64/DEV.STD.PTHREAD/build/universal-Darwin/bin/hermesc,--emit-binary,-out,/Users/[userName]/Desktop/code/[project]/build/lib/rn-bundles/Release/index.hermes.bundle,/Users/[userName]/Desktop/code/[project]/build/lib/rn-bundles/Release/86a8cabff3eca67162980c1ff04438128e42e8abe4b575029cfd0beef9bf63ac.bundle,-O,-w: /Users/[userName]/Desktop/code/[project]/build/lib/rn-bundles/Release/86a8cabff3eca67162980c1ff04438128e42e8abe4b575029cfd0beef9bf63ac.bundle:225088:49: error: ';' expected undefinedif (msg instanceof UpdateExperiment_1) { ^. ``` **App Name** : Philo **App Link on Amazon Appstore** (found through Developer Console β†’ Actions column in App List β†’ View on [Amazon.com](http://Amazon.com)): [Philo: Live TV, Movies, Shows and Free Channels - App on Amazon Appstore](https://www.amazon.com/PHILO-Philo-Live-On-Demand-TV/dp/B07BKPFXTJ) **Bug Severity** Select one that applies - Impacts operation of app - Blocks current development - Improvement suggestion - Issue with documentation (If selected, please share the doc link and describe the issue) - Other ## 2. Steps to Reproduce 1. use `npm run build:release to build app` ## 3. Observed Behavior _Explain what actually happened, noting any discrepancies or malfunctions._ ```auto The build starts but errors and does not finish ``` ## 4. Expected Behavior _Describe what you expected the SDK to do under normal operation._ ```auto I expect a build folder with build files of the project in it ``` ### 4.a Possible Root Cause & Temporary Workaround _Fill out anything you have tried. If you don’t know, N/A is acceptable_ ```auto Haven't found one yet ``` ## 5. Logs or crash report _**`(Please make sure to provide relevant logs as attachment)`**_ [bug\_logs.txt](https://community.amazondeveloper.com/uploads/short-url/i1S1iBjIyM6826T3EBtj1yrEnhU.txt) (5.7 KB) ## 6. Environment _Please fill out the fields related to your bug below:_ - **SDK Version:** _`0.22.5875`_ also seen with 0.21.\*\*\*\* as of Monday (2/2/26) - **App State:** `BUILD` - **OS Information** : `Not on the device` * * * ## πŸ‘‰ Additional Context * * * **Any Additional Context you would like to provide?** _Add any other relevant information, such as recent updates to the SDK, dependencies, or device OS that may affect the bug._ ```auto This started on Monday (02/02/26) with the same build that was working Friday (01/30/26) ``` ---
**Author:** ![Tony](https://avatars.discourse-cdn.com/v4/letter/t/ee7513/32.png) [@Tony](https://community.amazondeveloper.com/u/Tony)\ **Post date:** [February 3, 2026, 7:33pm UTC](https://community.amazondeveloper.com/t/an-error-occurred-while-executing-hermes-command-vega-0-21-0-22/27581/3 "2026-02-03T19:33:54Z")
The bug oddly went away after creating a build on the simulator (Vega virtual device) ---
**Author:** ![amen](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@amen](https://community.amazondeveloper.com/u/amen)\ **Post date:** [February 3, 2026, 8:20pm UTC](https://community.amazondeveloper.com/t/an-error-occurred-while-executing-hermes-command-vega-0-21-0-22/27581/4 "2026-02-03T20:20:53Z")
Hi @Tony Thank you for the detailed bug report on the Hermes compilation error. I’m glad to hear the issue resolved itself after creating a build on the Vega Virtual Device. This suggests there may have been a cached or corrupted intermediate build artifact that was cleared during the simulator build process. For future reference, if you encounter similar Hermes compilation errors, here are some troubleshooting steps that may help: 1. Clean the build directory: Remove the `build/` folder and rebuild 2. Clear Metro bundler cache: `npm start – --reset-cache` 3. Verify node\_modules integrity: Delete `node_modules/` and reinstall dependencies 4. Build on the simulator first: As you discovered, this can help clear stale artifacts The error message you encountered `(β€˜;’ expected undefinedif (msg instanceof UpdateExperiment_1))` suggests the bundler may have generated malformed JavaScript, which could indicate a transient issue with the build pipeline or cached state. Feel free to reach back to me if you have any questions or run into any issues! Thanks for helping us improve the Vega platform. Warm regards, Aishwarya ---
**Author:** ![system](https://dhm3gbtzu79o6.cloudfront.net/user_avatar/community.amazondeveloper.com/system/32/5065_2.png) [@system](https://community.amazondeveloper.com/u/system)\ **Post date:** [February 17, 2026, 8:21pm UTC](https://community.amazondeveloper.com/t/an-error-occurred-while-executing-hermes-command-vega-0-21-0-22/27581/5 "2026-02-17T20:21:21Z")
Closed on February 17, 2026, 8:21pm UTC This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.