I am having an issue when I import files from AI to XD where my line shapes and arrows are disappearing. Is there any way to preserve this before I import, so I don't have to change each one back manually?
Sorry to hear about the trouble. When opening Illustrator files in XD, most of the layers and effects are retained with exact visual fidelity and are editable. However, some Illustrator features are not compliant and are transferred as vectors or not transferred at all. There are certain limitations while importing Illustrator files in XD so please refer to this article https://helpx.adobe.com/in/xd/user-guide.html/in/xd/kb/open-illustrator-files-in-xd.ug.html
Let us know if this helps or if you need any further assistance.