20 October 2023
Microsoft has updated their API, and the issue is resolved.
Document Set creation works as intended, and no updates to MacroView DMS/DMS Pro are required.
18 October 2023
We are aware of an issue currently affecting the creation of Document Sets with custom content types in MacroView DMS/DMS Pro.
This is due to an unintended change by Microsoft to the APIs that SharePoint developers rely on to validate and update Document Set properties.
We're currently investigating solutions within DMS/DMS Pro while Microsoft work on a fix to their API.
Follow this post by selecting the "Follow" button at the top of this article to get the latest updates as we continue to investigate this issue.