We have been using InCopy successfully for a couple of years. We have a standard workflow where the Designer exports all stories to InCopy and the editors access all stories by opening up the InDesign files via InCopy. We all recently upgraded to Mac OS Catalina and in doing so all upgraded our versions of InDesign and InCopy to 15.1.1 (all are running the same versions). With the same workflow applied, the editors can still check out stories and make edits, but can no longer check in stories regardless of which way they try to it (Edit>Check in All or from the Assignments panel using the icon at the bottom or in menu list). Also, when closing the InCopy file and prompted to check in all stories, it still does not work, but additionally, we get a "Save stories" prompt as well, which is not usual for InCopy. On the designer side, they can open the InDesign file and see the checked out stories with all the changes (so changes so far have not been lost), and they are able to update the links. However, they have to unlink the entire project to work on it because if they check out stories, the same issue happens on their end. The only changes to our environment are the upgrades in OS and versioning. We also thought perhaps it had something to do with picking up old files that were created in older versions of InDesign, but the same result occurs with newly created files. We also tried exporting as assignments and nothing changed. Any help is greatly appreciated!