The new Mavericks OS is causing so many issues with musical software read some of these notes
Our initial testing of the new Mac OS X Maverick [sic] has not revealed any problems with Reason 7.0.1, ReCycle 2.2 or the Balance audio interface. We are doing more in-depth testing as we speak and will release a more formal compatibility statement as soon as we are done.
… what is known so far is that all Steinberg software products (except for Cubase LE / AI / Elements 7.0.6) are affected by an issue with the CoreAudio2ASIO component when using audio hardware in class-compliant mode which may lead to dangerous digital noise. Some Steinberg hardware products need to be updated as well to ensure full compatibility with the new OS X version. We therefore recommend you not to upgrade to OS X 10.9 yet.
Ableton Live 8 and 9 are compatible via new betas. Live 8 and Live 9 stable currently are not recommended for Mavericks. If you’re on the beta list, though, beta updates (8.4.2 and 9.1) are available now. Those two betas are very stable, so oddly, beta Ableton users may feel free to jump for the new OS. Everyone else should wait.
Read the full article here and see if you really want to upgrade to Mavericks OSX