Lately my user sent me the information that he gets "An error occurred - Unknown error" from one of our apps while trying to open that app. As the admin I tried to open app and it worked fine for me. After short investigation I found that user has two more unpublished dashboards on his "My sheets" workspace and I'm convinced that one of these can be the reason of error.
The question is - how to get ownership of user's content (unpublished sheets) and make any changes on them. I would like to find the reason of error and fix it. User can not access the app so there is no possiblity for him to publish his new dashboards. When I try to duplicate or export the app it is copied without user's content. I can see user's sheets in QMC -> App objects, but I can't manage them from there.
Any ideas how to get access to user's content and backup user's dashboards, which are not yet published?