Cubase 5 and 6 installed. Melodyne problems

I have installed Cubase 6, although I am still using 5 until later. My Melodyne is stuttering the audio when transferring a short mono Horn track. Could this be because Cubase 6 installed. Can I have both programs
present with only one running. I had no Melodyne proglems before this.

Ho - I have the same setup as you on one of my PCs without any Melodyne problem. This refers to Melodyne 3 and Melodyne Singletrack.

I know that’s not all that helpful - but at least it helps narrow down areas to look at.