Cubase Pro 11 losing audio files

On opening a project I’m working on atm, cubase starts up with a message something like (I forget the precise words) “These audio files are missing, please locate:” and a locate button plus a cancel…
Locate opens an explorer window.
The first time this happened 2 files were missing, neither of them was visible in the explorer window, and I was too impatient to search much further, it seemed simpler to re-record.
Today I opened the same project, to find the same message; only one file this time, and it was visible and available in the explorer window, so I opened it and the project started ok and played as expected.
Does anyone here have any idea what’s going on?
Tony G

Dell Inspiron i7
Cubase Pro 11.0.10
Windows 10
SSL 2+

PS Forgot to mention, all other audio files were present and played correctly.

I was away from this project for a couple of days, when I came back to it, cubase said the same file as above was missing, though it was easy to locate with the locate file button and played correctly again, so a nuisance rather than a disaster…even so, a bit of a pain, any ideas out there?
Tony G

Solved by simply deleting offending file from pool…dunno why we didn’t think of it sooner…or why cubase couldn’t see it. Anyway, didn’t need it, gone now, problem solved,

Tony G