So, it’s a cool idea that it’s a “closed system” and doesn’t need any refilling. However, mine was mishandled by movers. This includes storing it on its side, and possibly even upside down though I have no proof of that. A very significant amount of the oil has leaked out.
I see no simple way to check or refill the reservoir.
Imagine how infuriated I was when I saw this…
Uh-oh. Support’s gonna need to field this one. When you moved it, did you have all of the original packaging for it? (That protects it from mishandling of the worst sort…ie: shipping companies.)
Good luck! 
Is it a new machine?
I got a terrible sinking feeling as I read your post. Stored on it’s side? Upside down??? 
Wait on word from support. My fingers are firmly crossed for you.
I’m pretty sure it’s mineral oil, so while it’s made a mess it’s not going to corrode anything or cause a short circuit in the electronics. I use a liquid CPU cooler in my workstation and it’s plumbed with the same stuff for the same reason - leaks are at worst a mess to clean up.
The reservoir is under the left side panel. On my GF at least, it’s a white plastic bottle with a screw cap that can almost certainly be removed to add more oil.
So I would say your odds of recovering from this are good. But before you start taking things apart, you should wait for Customer Support to chime in…
Mineral oil acts as a good thermal conductor and is nonreactive electrically. There are some folks who will immerse their PC in it to provide cooling - it’s something the hardcore gamers & crypto currency miners do.
I’m so sorry to hear your Glowforge was damaged in shipping. I’ll send an email shortly to arrange a replacement.
