External Guests do not see Term Store values anymore

Hello @Arnaud Gaillard we are experiencing the same issue on multiple tenants. As we found described on one of the (actually quite old) web pages about this issue, we tried to manually add guest users to the "hidden list" that you access via the url https://[companytenant.sharepoint.com]/sites/[sitename]/Lists/TaxonomyHiddenList/AllItems.aspx. Inside the List settings' access management section: you should add manually all the guests that need to view the term set, because at this moment the "Everyone" access granted is not working properly. It worked for us as a workaround: as soon as you give the granular permission to the guest users, they can read the terms like before and even see correctly any related web part on the SP pages, if it was filtered by Managed metadata (e.g. a News wp). It is quite impossible to use this workaround as far as a large number of guest users is concerned, though. We really hope Microsoft will fix this issue soon.

Hi @Arnaud Gaillard, 

Welcome to Microsoft Q&A forum. 

Thank you for reaching out sharing detailed testing information. I understand how disruptive this issue has been, especially since the functionality was working previously. I have spent time thoroughly reviewing the configuration and testing multiple remediation approaches to ensure this was not a permission or configuration-related problem within our tenant. 

As part of the troubleshooting process, I created a dedicated security group in Entra ID, added the external user to that group, and assigned the group as Stakeholder at the Term Group level in the Term Store. I also allowed sufficient time for permission propagation and re-tested the scenario, but unfortunately the Managed Metadata values are still not visible to the external user. 

Given that standard permission adjustments did not resolve the issue, this indicates the root cause is likely related to backend identity resolution or a recent Microsoft 365 platform change affecting guest access to taxonomy services, rather than a tenant configuration issue. 

At this stage, the most appropriate next step would be to open a support ticket with Microsoft Support via the Microsoft 365 admin  center so they can review service-side logs and determine whether this is related to a known issue or a recent update impacting guest identity behavior.   

As moderators, our primary goal is to provide helpful guidance and support through general troubleshooting steps. While we don’t have access to internal systems or administrative tools required to resolve account-specific or backend issues, we truly appreciate your understanding of these limitations. We genuinely hope the information we share helps point you in the right direction, and we're always here to assist as much as we can within our scope.  

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