I want to work on my database, to add some new features, whils users continue to share it. I will make a copy delete all the records and work on the changes. Once I have done this I will import the data from the live database.

However when I have tried doing this I find that the relationships are not formed, unless I go into each ID field and tab out of it.

Is there a way to force filemaker to pick these up? Or a better way to work on a database, without effecting users?

You can actually work on it live whie users are using it. But especially if you're not sure what you're doing this may not be a good idea. You may also want to read up on the seperation model. The interface file is seperate from the data file. So there is no data to import. You just install the new interface file and you're in business. This works pretty well but the reality is that sooner or later you will probably also need to make some changes to the data file.