# How to debug "Cannot decode introspection" error when running downloadApolloSchema

**URL:** <https://community.apollographql.com/t/how-to-debug-cannot-decode-introspection-error-when-running-downloadapolloschema/6129>\
**Category:** Client SDKs\
**Tags:** client, mobile, kotlin\
**Created:** [April 11, 2023, 10:46pm UTC](https://community.apollographql.com/t/how-to-debug-cannot-decode-introspection-error-when-running-downloadapolloschema/6129 "2023-04-11T22:46:39Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![nateirwin](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/nateirwin/32/477_2.png) [@nateirwin](https://community.apollographql.com/u/nateirwin)\
**Post date:** [April 11, 2023, 10:46pm UTC](https://community.apollographql.com/t/how-to-debug-cannot-decode-introspection-error-when-running-downloadapolloschema/6129/1 "2023-04-11T22:46:39Z")

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At some point, changes were made to one or more .graphql file in our project and introspection via `./gradlew downloadApolloSchema` broke. I’ve spent a significant amount of time going back through Git commits, manually inspecting our .graphql files, etc. trying to figure out which commit broke things… it’s painful to say the least.

Is there a way to get more detailed output from `./gradlew downloadApolloSchema` that highlights which file is causing the “Cannot decode introspection” error?

I’ve tried running the command with `--stacktrace`, `--info`, etc. but I still can’t figure out the source of the error.

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**Author:** ![nateirwin](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/nateirwin/32/477_2.png) [@nateirwin](https://community.apollographql.com/u/nateirwin)\
**Post date:** [April 12, 2023, 9:44pm UTC](https://community.apollographql.com/t/how-to-debug-cannot-decode-introspection-error-when-running-downloadapolloschema/6129/2 "2023-04-12T21:44:43Z")

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I resolved this by going back to Apollo Kotlin 3.7.4 (we had upgraded to 3.7.5 recently). So it actually wasn’t an issue with a query or anything like that.

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**Author:** ![jesusdmedinac](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/jesusdmedinac/32/4247_2.png) [@jesusdmedinac](https://community.apollographql.com/u/jesusdmedinac)\
**Post date:** [May 3, 2023, 11:41pm UTC](https://community.apollographql.com/t/how-to-debug-cannot-decode-introspection-error-when-running-downloadapolloschema/6129/3 "2023-05-03T23:41:15Z")

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I solved my issue the same way. Maybe just a problem with version 3.7.5. Thanks @nateirwin 🙌

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**Author:** ![Justin\_Gonzalez](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/justin_gonzalez/32/5359_2.png) [@Justin\_Gonzalez](https://community.apollographql.com/u/Justin_Gonzalez)\
**Post date:** [February 6, 2025, 8:48pm UTC](https://community.apollographql.com/t/how-to-debug-cannot-decode-introspection-error-when-running-downloadapolloschema/6129/4 "2025-02-06T20:48:54Z")

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