Not being able to open the raw files is probably because your version of LR did not support a recent enough version of the ACR engine. One thing Adobe does is update camera support in point releases of the ACR engine. They then have life cycle limits on the version of Lightroom or Photoshop the point versions support.... I just can't get my copy of Lightroom to open a uncompressed RAW file from my a7rII ...
Not sure how Capture One does the camera updates.
Since I use the Adobe products everyday and keep them up-to-date their update methodology isn't a problem. If one is trying to use an older version of software with newer camera(s) it can be problematic.
If you still have LR available, you might try downloading the latest ACR engine update. The Adobe site probably has a compatibility table that will confirm if the latest version will run with your version of Lightroom.