Raw files coming up grainy / added noise

[pablomatisse]

Hi, i'm currently having a problem with Photoshop CC, whenever I open up a raw file there is a ton of added noise/grain, this has never happened before and these are all images that I have opened many times before in Photoshop without this problem, I'm confused as to why this is happening now all of a sudden, any help would be greatly appreciated, thank you!

[selsk66]

What ISO are these files?

[D Fosse]

We need to see it. Post screenshots at 100% view. Just crop a portion.

[Grigor Poghosyan]

It may cause from tons of reasons, many of them might be related with the camera, and not to the software itself, did you try to open other raw images which you're sure that were correct before? can you please show us some examples?
for example, it may happen because your camera was overheated when you ware taking those frames, sensors are not really clean,
the air maybe dirty too, incorrect contrast and sharpenning setting, high ISO point, etc.
which versions of PS and camera raw are you using?

[Bo_LeBeau]

I'm assuming you are talking about the image in Photoshop and not in ACR.

There is a grainy problem that shows up if you have your Cache Levels set to less than 4.

[Trevor.Dennis]

This is often caused by having Cache levels set at 1 in Preferences > Performance.  Definitely worth checking