Macintosh workaround to print USPS postage
Hidden away on their FAQs is that it doesn't work on Safari. At all. Don't bother trying. But it will work on Firefox, kind of. So open up Firefox and fill out all the stuff that you used to do. When you get to the print label part, it gets kind of tricky, but it's doable. I just did it.
When the file downloads to your downloads folder it will have a name with a .pdf extension and some long nonsensical dot-something extension. Just erase that additional extension, so that it just ends with .pdf, click on it and print. No, there isn't anyone at USPS who can help with this, so don't bother looking for customer service. Hey, it's the post office!
This took me about two hours to learn. I hope this helps someone!
Posted by Brad Hall