PBIP Semantic Model Error There is a problem with the definition content in your Power BI project.

Solution delete the cache.abf file 

Hi DebbieE 
Thanks for reaching out to the community.

Just to confirm and add a little context for anyone who faces similar issue. 
The error happens because Power BI Desktop reuses a cached local workspace database ( cache.abf ) from a previous session. That cached model was created at a higher compatibility level (1600) than your project's  database.tmdl  requests (1587/1567). Tabular doesn't allow a compatibility-level downgrade on an existing database, so Desktop refuses to load the project against the stale cache which is exactly why a colleague on the same branch and same version had no problem (they had no conflicting cache), and why a reinstall didn't help (the workspace cache survives it).

If your issue has been reolved you can mark your post as a solution.

Please do reach out community for any new Fabric or PowerBI issues.

Thanks,
Srikanth Cheri,
CST team.