Cannot make file available offline because Dropbox says not enough space

Hi Folks,

Dropbox now says it can download this file... OK. Well, that's what I wanted... (I'd delete this post but can't, apparently?)

More on my ongoing fun with online/offline files.

I have decided to move all my online-only files offline as it wasn't working for me (also due to the backup software I use).

All worked fine except the last file, which is 243 GB in size. Dropbox says it cannot download this because I don't have enough disk space. But I actually have 293 GB. So what is going on here?

Any ideas welcome!

P.S. I can't add screenshots (?)