If Photoshop on your Mac refuses to open a .JPEG and gives you the error:
“Could not complete your request because an unknown or invalid JPEG marker type is found,” there’s a good chance the file is actually an HEIC image mislabeled as a JPEG, especially if it was taken on an iPhone.
In this quick Designer to Fullstack tip, I walk you through two fast ways to fix it:
✅ Method 1: Rename the File Extension
If the image preview works in Finder but not in Photoshop, try changing .jpeg to .heic. This often resolves the metadata conflict instantly.
✅ Method 2: Re-Export with Preview
Open the “corrupt” JPEG using Preview on your Mac and export it as:
HEIC, or a clean JPEG
Either option rewrites the metadata so Photoshop can open the file normally. If your Photoshop JPEGs won’t open due to a bad marker type, this quick fix should get you back on track.
Full Blog with Steps:
Fixing the “Unknown or Invalid JPEG Marker” Error in Photoshop on a Mac
Have dozens, hundreds or thousands of files with the wrong markers?
There are several ways you can automate the process – check them out on the blog, too:
Fixing the “Unknown or Invalid JPEG Marker” Error in Photoshop on a Mac
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Hello, world. I’m *Kelly Barkhurst* —an experienced Mac-based full-stack designer, educator, and entrepreneur passionately blending artistic vision and creativity with deep technical expertise.
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