Project mode is a new feature that is still under development as of v17R6. However, a preview of the feature is available in the beta builds of v17R5 and v17R6. With the official versions of v17R5 and v17R6 the feature is not complete yet and as such disabled. To continue using and testing the feature, the next avaialble beta versions or the prior beta versions will continue to have the feature enabled until the feature is finalized and enabled as an officially ready to deploy feature in offical builds of 4D.