I noticed at one point my dynamics system and Rigid Body Tag was missing in Cinema 4D and found this solution.
In case you are missing the Rigid Body Tag, the simulation tags or even the entire Dynamics System for that matter in Cinema 4D R17, be sure to install all of the Microsoft Redistributables.
Restart Cinema, it should be back where it is supposed to be. This works in C4D r17 on Windows.
Download the necessary Redistributables here: https://www.sendspace.com/file/7lxk8x