Canon EOS 5D MARK IV Instruction Manual page 573

My card reader does not recognize the card.
Depending on your card reader and computer OS, large-capacity
CF cards or SDXC cards may not be properly recognized. In such
a case, connect your camera to the computer with the interface
cable, then transfer the images to the computer using EOS Utility
(EOS software, p.598).
I cannot process the RAW image.
41 and 61 images cannot be processed with the camera.
Use Digital Photo Professional (EOS software, p.598) to process
those images.
I cannot resize or crop the image.
With this camera, you cannot resize or crop JPEG c images,
1/41/61 images, or frame-grab images from 4K movies
saved as still photos (p.452, 454).
Dots of light appear on the image.
White, red, blue, or other colored dots of light may appear on
images if the sensor is affected by cosmic rays, etc. Their
appearance may be surpressed if you perform [Clean nowf]
under [53: Sensor cleaning] (p.458).
The Dual Pixel information cannot be used for processing
the RAW images.
Although Dual Pixel RAW images can be processed with [x1:
RAW image processing], this camera cannot process the image
using Dual Pixel data. For using Dual Pixel data, process the
images with the Digital Photo Professional (EOS software, p.598).
Troubleshooting Guide
571