I want to migrate the document library of GroupWise to SharePoint. I have no idea how I can make this migration. I have around 300 users and I should also take care of user permissions. My idea was to export the documents of each user into a folder with user name and the upload them to SharePoint for every user. The problem is that there are so many data and data duplicity would take so much space in vain. Do you have any other idea how could I make this migration? Please answer or comment whatever you think, since I guess there is no wrong answer.