Updating to ZBrush 4R2
From ZBrush Info
Because ZBrush 4R2 is a stand-alone version, upgrading to 4R2 is the same process as for a fresh installation. Your previous version(s) of ZBrush will remain an independent application and the upgrade process will create a new ZBrush 4R2 folder in your Program Files (x86) folder or Applications directory. At any time ZBrush 4 or 4R2 can be used on your system after the upgrade to ZBrush 4R2. Do not run both versions at the same time on any system, however as this will cause resource conflicts.
Please be aware that support for all versions prior to ZBrush 4 has been discontinued, except for users who cannot yet upgrade to it thanks to having an outdated processor. You may continue to use an earlier version, but if it stops working for any reason you will not be able to receive support to reinstall or reactivate it.
Please, follow the Installation steps ZBrush 4R2 Installation and Activation
