I have just bought a Panasonic G7 and am having probelms importing raw file images. The preview does not display the image and shows preview not available and when I import the raw files I get the error messgae that the file format is not recognised!! I am running Lightroom 5.7.1.
That camera was first supported in Lightroom 6.1, so that is why you are running into that issue using 5.7.1. You will either need to upgrade to 6.1 (or later) or use the free DNG Converter utility to convert your files to DNG. See here for more info: Troubleshoot Adobe Camera Raw Compatibility Photoshop Lightroom