Well, at this point CS6 is eight years old and as it always has been, new cameras = new version of Adobe Camera Raw = new version of Photoshop. That's the simple logic here. You have to use whatever conversion tool/ programs comes with your camera, give the DNG converter a try (https://helpx.adobe.com/de/photoshop/using/adobe-dng-converter.html) or ultimately simply swallow the bitter pill and ign up for a current subscription of PS/ Lightroom to be able to efficiently work with your Raw files without jumping hoops with extra conversions.
What camera do you have?
What operating system are you using?
What camera are the files from?
Do you have ACR 9.1.1 installed for CS6? If not download and install it. See if you still have a problem with the RAW file. Of you do try creating a DNG RAW file from your Camera RAW file and process the DNG Raw file. However, I doe not know if Adobe still maintains its DNG converted Camera makers did not want DNG file format.