I have a document library with two custom content types. If I use the web interface and choose New Document -> MyCustomType the document template opens up and I can create and modify the document and list item properties.
I then created a workflow using SharePoint Designer 2010 and setup an action to create a new list item on my document library. I gave it a name and set the content type to MyCustomType. The workflow executes without error and creates the document - but I can't open it in Word. I get the following error: The file test.docx cannot be opened because there are problems with the contents. There are no additional details.
I opened up the .docx file and looked at the embedded XML and I can see that it is using the correct template. Any ideas why Word is failing to open the document or something I can do to troubleshoot / get more info on the error?
Update: I recreated the template from an empty word doc and the problem is resolved. I would like to leave the question open for now in hopes of better troubleshooting advice for repairing an existing template.