According to multiple users on the Sony Alpha subreddit, Sony's a7 III camera is having issues with a particular SanDisk SD card.

Reddit user "shadyashell" originally made a post regarding an issue they were having with their Sony a7 III camera and SanDisk Extreme Pro 128GB SDXC UHS-I Card (Class 3) memory card. In the text of the post, they wrote:

"Everytime I insert the card into slot 1 [I get] the error message 'Unable to read memory card. Reinsert memory card. Slot 1' appears. I've reset the camera multiple times, formatted the card both on slot 2 and my laptop. Any advice on solving this issue?"

Not long after posting, other Reddit users chimed in and echoed that they too had experienced an issue. Reddit user 'iamtridluu3' said "I'm having the same issue. All six cards. Identical 128gb Extreme Pro. I could use it in slot 2 fine. Just slot 1 of both my a7 III and all six cards. Something is wrong with these cards."

Reddit user 'dany74m' claims to have contacted Sony and been told that "[Sony] officially recognize[s] the problem" and "the camera or the card are not defective [it's] just an incompatibility with the SD extreme V.30 128GB." Reddit user 'dany74m' added "[Sony] said they are aware and they are working to fix the issue with a firmware update in few weeks."

DPReview contacted Sony regarding the issue. A spokesperson for the company kept it short and vague, saying "our team is currently investigating the claims." We will update this article if any new information becomes available.