Set Class as Default when creating a new Object

In the Class Permission settings you can specify that certain user groups are not allowed to see and/or attach objects to that class. If you only allow users to attach objects to one class I would expect that this is the only available option to those users. Have not tested.

If you only want to set a default class (with an option for the user to change it) you can use metadata card configuration by creating a rule that includes only an object type filter and applying SetValue to the Class property.

If you’re using the new M-Files Desktop or Web, ensure you’re running the latest version, as support for this configuration was introduced in the October '25 release.