# Shareholding in CS01 changes? Fatal 9999 Duplicate ShareholdingId: error

**URL:** <https://xmlforum.companieshouse.gov.uk/t/shareholding-in-cs01-changes-fatal-9999-duplicate-shareholdingid-error/1832>\
**Category:** Confirmation Statement (New Annual Return)\
**Created:** [October 31, 2025, 7:35pm UTC](https://xmlforum.companieshouse.gov.uk/t/shareholding-in-cs01-changes-fatal-9999-duplicate-shareholdingid-error/1832 "2025-10-31T19:35:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![user14](https://xmlforum.companieshouse.gov.uk/letter_avatar_proxy/v4/letter/u/e99b99/32.png) [@user14](https://xmlforum.companieshouse.gov.uk/u/user14)\
**Post date:** [October 31, 2025, 7:35pm UTC](https://xmlforum.companieshouse.gov.uk/t/shareholding-in-cs01-changes-fatal-9999-duplicate-shareholdingid-error/1832/1 "2025-10-31T19:35:32Z")

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I have been testing a submission using the new CS01 schema. The submission including a shareholding list is accepted using the previous schema (ConfirmationStatement-v1-3). However now that I am testing the ConfirmationAndVerificationStatement-v1-0 it immediately and consistently refuses to allow me to file and gives me several 9999 fatal errors with the error code “Duplicate ShareholdingId:”.  
It also gives me one 9999 fatal error code with the error message "ShareholdingId is not used, no Shareholder references the ShareholdingId: "  
Has something changed? Also, can I test the new schemas using the standard test gateway or must I use a sandpit endpoint? Thanks for any replies.

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**Author:** ![snicholas](https://xmlforum.companieshouse.gov.uk/user_avatar/xmlforum.companieshouse.gov.uk/snicholas/32/81_2.png) [@snicholas](https://xmlforum.companieshouse.gov.uk/u/snicholas)\
**Post date:** [November 4, 2025, 11:19am UTC](https://xmlforum.companieshouse.gov.uk/t/shareholding-in-cs01-changes-fatal-9999-duplicate-shareholdingid-error/1832/2 "2025-11-04T11:19:06Z")

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You can not test the 18th November schemas via the normal test service.

For these, the test instructions are as follows:

**You can use your live presenter credentials - but show Package Reference as 0012 and Test Flag as 1.**

**Endpoint: [https://xmlgw-sandpit-staging.companieshouse.gov.uk/v1-0/xmlgw/Gateway](https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fxmlgw-sandpit-staging.companieshouse.gov.uk%2Fv1-0%2Fxmlgw%2FGateway&data=05%7C02%7C%7Cf23c097823614fe1637608de1a54d0f4%7Ce6acfe5e7f2a455a9d85ecf93371f601%7C0%7C0%7C638977148761655315%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=kLtgPNEMRiGYtPe1EpMrYHTl3Pg0GaH85bwD5L1pYe8%3D&reserved=0)**

**If you receive an XML schema validation error, then the schema is failing due to a syntax error or incorrect basetype compatibility - and should be considered a failed test.**

**If you receive any other error response, such as an authorisation failure, then that means the schema has passed the schema validation stage, and should be considered a successful test.**

**For reference, the following is a link to the test service schema page.**

**[https://xmlgw-sandpit-staging.companieshouse.gov.uk/SchemaStatus](https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fxmlgw-sandpit-staging.companieshouse.gov.uk%2FSchemaStatus&data=05%7C02%7C%7Cf23c097823614fe1637608de1a54d0f4%7Ce6acfe5e7f2a455a9d85ecf93371f601%7C0%7C0%7C638977148761670839%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=j6J7jfTuk6%2B1l7B%2F6FieA4sBhbjdg2vke4lsydlyYPA%3D&reserved=0)**

SDN

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**Author:** ![user14](https://xmlforum.companieshouse.gov.uk/letter_avatar_proxy/v4/letter/u/e99b99/32.png) [@user14](https://xmlforum.companieshouse.gov.uk/u/user14)\
**Post date:** [November 4, 2025, 1:14pm UTC](https://xmlforum.companieshouse.gov.uk/t/shareholding-in-cs01-changes-fatal-9999-duplicate-shareholdingid-error/1832/3 "2025-11-04T13:14:25Z")

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Thank you very much for this, Simon. Much appreciated.