Box for Salesforce users may see the error message "Box Preview Error: Unable to find a file ID. You may not have access to the file or field." when attempting to view Salesforce Lightning Page:
Root Cause
This error message comes from "Box Preview" Lightning component of Box UI Elements. The chances are you have a Box UI Elements Content Preview component embedded in the affected Lightning Page, but its file ID field is set to the invalid value (ID of the file you don't have access to) or is left empty.
Resolution
To resolve this error, you can edit the affected Lightning Page via Lightning App Builder, locate the "Box Preview" component and make sure that the right file ID is set to it or remove "Box Preview" component if it's not used.
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