It took forever for me to open in Illustrator also (Macbook Pro). I wonder if you’re not working with a linked image in Illustrator and then on the export, it is embedding the image - which is why it opens no problems for you.
Anyways - I downloaded your file and was reading through this thread. And I was wondering exactly how your SVG got to 42mb. I know the image inside was around 1200ppi - but that’s doesn’t really matter - it’s the actual pixel count and it’s not a huge image in those terms. I’ve loaded much larger into the UI. The 32-bit image stuck out to me though - that’s definitely not a JPEG. 32-bit is either a PSD or TIFF file.
I exported an image out of Lightroom at a pretty low resolution 1000xSomething (like 14mb) - and the uploader freaked out on me and errored. I then exported another copy out at 500 pixels (TIFF format) and the uploader still freaked out on me.
It sounds to me like, even though TIFF format is in the Custom List for the uploader, it’s not very happy with them.
@henryhbk - was the original file/embedded file a TIFF-format?