Audio files missing on every project!

I recently bought Cubase Pro 10 and I am having very strange problems since then.

I am constantly missing audio files on every project even on backup projects! What is wrong? So many years…I had never experienced such thing on previous versions or other software!..Or the audio file won’t play, because it won’t contain any audio data? How is this possible?
I never deleted any audio files or clips, or tracks! I always start recording on an empty folder. What is wrong?

I keep loosing audio data every time I reopen to project file. I feel embarrassed in front of the musicians who played the song, because they have to come again and replay it. Ridiculous!

I had the same here, but did you try this?
Open Steinberg hub
Here you have either a standard location for your files or you can choose another location where you can define what Cubase is supposed to do