Cubase 10.5 WAV insert issue

I’m having a weird issue where I sent an artist the WAV mix of a project, and he inserted said wav mix into Cubase, and then recorded his solo. He then sent both the wav files back, one with my wav mix (for reference) and one with just his guitar, both starting at zero for easy referencing.
The issue is that when I insert his guitar solo into the project, it extends beyond the marker boundaries of the solo piece and isn’t aligned.
I confirmed with him that he matched my export settings.
What the heck am I missing? This is really fetching up a back and forth remote collaboration.

I tried time stretch, but it gave small artifacts and I was never able to truly sync it properly.

Thanks for any help you can send my way!


you have to make sure that he is recording with the same samplerate than your project

What DAW is the other one using?

I am checking with him with regards to sample rate. (Projects>Project Setup)
He is running an older version of Cubase for a DAW

you can build a Project for him and he can send this back to you after he recorded the guitar
and now you are able to import the audio as you need it…
He has to send you the whole folder…