Environment: Full Copy Sandbox Data Cloud was [enabled directly in the sandbox / inherited from Production]. Salesforce release: [Winter ‘27 / other].
Use case: Enable Agentforce Data Library and point it to internal CRM Knowledge Base articles.
Steps taken:
Enabled Data Cloud and assigned the Data Cloud Architect permission set to the System Admin user.
Installed the latest Service Cloud bundle in the CRM Connector.
Activated the Home Org CRM Connector.
Created an Agentforce Data Library pointing to Knowledge Articles.
The library status shows every step as successful: ingesting data into Data Cloud, creating data lake objects, mapping DLOs to DMOs, creating the search index, and building a retriever from the search index.
Problem 1: Data Explorer queries fail
DLO Knowledge_kav_Home fails with: “Something’s not right with the query. Check the columns or filter and try again.” TraceIds: 220ae71e7e7e017b, 6e0ef3579db8d062.
DMO KA_CompanyName_KB_Data_Libr_index__dlm fails with the same error. TraceId: eb5ed4f4e67ee6d1.
DMO KA_CompanyName_KB_Data_Libr_chunk__dlm fails with the same error. TraceId: b0b718d9efff328a.
Other DMOs fail too, each with a different TraceId.
Data Explorer lists the object’s metadata (46 columns for Knowledge_kav_Home, data space default), but running the query returns the error.
Problem 2: Search Index Advanced Setup fails
After creating the Data Library, I tried to create/update a search index using Advanced Setup. I selected the DMO ssot__KnowledgeArticleVersion__dlm and clicked Next. On the “Select Fields to Chunk” screen I get: “We hit a snag. Something went wrong while retrieving attachments.”
What I’ve checked so far:
Data stream status / records processed: [result]
Minimal query (only Id column) in Data Explorer: [works / fails]
Same query in Query Editor: [works / fails, error text]
Other, non-Knowledge objects in Data Explorer: [work / fail]
Incognito / different browser: [result]
Retriever test in Prompt Builder or Agent Builder: [returns results / returns nothing]
User permission sets: [list]
Published Knowledge articles in the sandbox: [count]
Questions:
Is there a known limitation or extra provisioning step for Data Cloud and Agentforce Data Libraries in a Full Copy Sandbox?
Has anyone seen Data Explorer return this generic “Something’s not right with the query” error on DLOs/DMOs created by a Data Library, even though ingestion shows success?
Is a backend job (indexing, ingestion, or DMO mapping) still running or stuck after creation? How can I confirm this from the UI?
Could the “Something went wrong while retrieving attachments” error in Advanced Setup come from a permission, a data space, or a Knowledge setting? What should I check?
Do I need any extra permission set beyond Data Cloud Architect for the admin user to query these objects?
Should I open a Salesforce Support case with these TraceIds, or is there a fix I should try first?
