From Canon:
Thank you for using Canon products.
It has been confirmed that when shooting still images with the EOS-1D X Mark II digital SLR camera launched in April 2016 with SanDisk CFast cards, the following phenomenon will occur. We would like to offer our sincere apologies to users who have been inconvenienced by this issue.
Phenomenon
If a SanDisk CFast card is inserted into the camera or a card reader, the bottom part of still images recorded may be corrupted. This phenomenon is confirmed in images recorded in both the RAW and JPEG formats.
Please Note:
Cause
This phenomenon is caused by SanDisk CFast cards. The camera does not cause this phenomenon.
Affected Products
Image corruption may be experienced with the cards listed below*:
* The “xxx” at the end of the product number varies depending on the sales region.
Market Support
Although it has been confirmed that this phenomenon is caused by SanDisk CFast cards, to prevent the occurrence of this phenomenon, Canon is considering releasing camera firmware on the Web for a download service in early July.
We would like to apologize for the inconvenience, but we would like to ask our customers to refrain from using SanDisk CFast cards when shooting still images until the new camera firmware becomes available.
Workaround
It is our understanding that image files of 16MB or larger recorded immediately before the camera’s power is turned off may become corrupted. Below are the methods available to help avoid image corruption when powering off the camera:
The Camera can be powered off in four ways:
Before powering the camera off, please take extra shots because the extra shots taken immediately before the camera is powered off may experience the corruption and not the images taken before the extra shots were taken.
The table below shows the most popular file types used and how many extra shots are recommended.
File Size (Approx.) | How many extra shots do I need to take in order to meet the 16MB or larger requirement? |
[RAW] 23.2MB | 1 |
[JPEG] L:6.2MB | 3 |
[JPEG] M1:4.3MB | 4 |
[JPEG] M2:3.4MB | 5 |
[JPEG] S:2.2MB | 8 |