OP,
If you have a new camera, your Photoshop CS6 uses a version of Adobe Camera Raw that cannot handle the files. And you can:
1. Install Adobe DNG converter and use that to convert your RAW to DNG, which is Adobe's own version of RAW that CS6 can handle just fine. The DNG converter is free to download from the Adobe website, but you should Google and research DNG before converting all your RAW to that format. There have been some problems reported. You may want tooarchive your original RAW files, as well as the DNG files made from them. That will take up a lot more space on your hard drives.
2. Purchase Lightroom 6 for about $140. It can be used to organize your images and handle RAW conversions, then pass the images off to CS6 for completion. Lightroom 6 is being kept up to date and will work with the latest cameras.
3. Use some other RAW converter to make TIFF files, which can be further processed in CS6.
4. Get Photoshop CC to replace CS6. PS CC includes Adobe Camera Raw up to 9.10, will handle the latest cameras and is being updated regularly. This is part of the $10 a month subscription (1 year prepaid).
If you have a new computer (which I think is the case), are still using a camera whose RAW files you handled with CS6 without problem on an old computer, and have reinstalled Photoshop CS6 on the new computer from a disk or stored download, it's quite possible that an older version of Adobe Camera Raw was installed along with it.
To check what version of ACR is installed, simply open Photoshop and look under the "Help" menu > "About Plug-Ins" > "Camera Raw" (click on the info box to close it, when done). If it's not Camera Raw 9.1.1.xx, download the installer here:
https://helpx.adobe.com/camera-raw/kb/camera-raw-plug-in-installer.html (Note: scroll to the bottom of the page to get the correct ACR 9.1.1 installer for CS6... Do not use 9.10.xxx installer, which is for later versions of Photoshop and is not compatible with CS6.)
Photoshop CS6 runs fine on Windows 7, 8 or 10. No need to update the OS, unless you want to for other reasons.