If you are using Sibelius 7.1.3, then both 32-bit and 64-bit versions are installed. Is this Samplitude thing a 32-bit or a 64-bit application? Their web site is broken at the moment, and I cannot find out. Trying to install another version of ReWire will probably break Sibelius.

When you install Sibelius, it installs the version of ReWire that it needs. > as the behaviour is far from plug and play to set up an appropriate system. > I am in need of professional advice where the proper installation locations are and which rewire version is where to install, Posted by Robin Walker - 15 Jul 07:52AM (edited 15 Jul 08:36AM) 7.1.3: Sibelius Out of Sync with Rewire - Samplitude X4 Maybe there are other ways necessary behind the scenes to sync sib and a DAW which I might have missed to properly play in sync with a normal and logical setup process besides a REPAIR button -). It also does not work with the actual sib ultimate 2019 version I am in need of professional advice where the proper installation locations are and which rewire version is where to install, as the behaviour is far from plug and play to set up an appropriate system. (What happens when you let sibelius repair its rewire settings though?) Somewhere in the rewire section of the sib manual there was a clue to go to Play>Performance>AudioOptions>'repair'. Once it opened, It runs out of sync to the DAW and does not feed the audio AUX Track with its Audio. After checking the rewire option checkbox in the Samplitude X4 Settings, I have to manually start Sibelius, as clicking the VST PlugIN in the channel strip does not work.

Samplitude x4