.sat export issues

I’ve been having an intermittent problem with exporting a .sat file over the past few days. What should be an 18meg export appears as 254k…

This happened previously, I exported a .step file and when I imported it again there was a rogue cylinder from a boolean that appeared. Extracting the fillet around the hole and blending the surface removed the export issue and it was all gravy.

I’m trying to export a .sat file again a few days later and I’m having the same issue although this time I can’t find what the problem is?

I’ve checked the model and and repaired any bad surfaces. It does export as a .step file, seemingly without any problems but it’s bugging me why it won’t export.

Any ideas how I can seek out the problem?

There are a couple of open edges I’ve patched with joinedge but I’m hoping this won’t cause a problem.