I'm trying to translate an idml file in Trados Studio 2021 (Trados Studio 2021 SR2 - 16.2.12.9338). I created the idml file from an indd file which is generated by our editorial system.

I succeeded in creating a project (with the option "Process unsupported file versions" activated in the idml file type settings) but Trados won't export a target file. I get an error message: Der Vorgang ist aufgrund des aktuellen Zustands des Objekts ungültig (Operation is not valid due to the current state of the object​​).

I've tried to troubleshoot by opening the original source file as a new single file project and then save the target file as suggested in https://community.rws.com/product-groups/trados-portfolio/trados-studio/f/studio/37164/save-as-target-idml-problem---get-the-error-operation-is-not-valid-due-to-the-current-state-of-the-object 

I have also tried to delete some of the metadata in the source indd, save again as idml and then translate and save as target. Didn't work either.

I've been searching the forum for other troubleshooting options. Is there anything else I can try?