Any chance you are using OneDrive? That seems to cause Windows users a lot of confusion because the files aren’t actually local when they think they are.
Search ‘OneDrive’ among the posts here for some recommendations of settings to use if that happens to be involved.
Following up on what @yuuuzeee suggests below:
From within the notebook or Jupyter teminal you can explore what it sees using the tips in the middle of my answer here.