I suspect that, whatever this problem is, both these oddities are related. Remember - Mac is Unix with a lot of Big-Brother crap on top of it. Nothing I, my root or my root terminal - not my Mint friend's - would let us write to the external mac USB hard drive or DOS-formatted memory USB dongle could change this, and between us we must have at least two brain cells.

In BOTH cases, the system insisted the USB drive was read-only. And HE could read files and open directories, and create directories, but not write to or copy files! WAIT - THERE'S MORE: two days later, I passed a DOS-formatted USB memory dongle with some files on it to a guy sitting next to me on a Linux Mint (Ubuntu-derived) laptop. what the heck is user 99 in a standard install? And despite my deleting the dummmy user's home directory, that user name still appears at time running processes. Oddly, the new user never showed up in System>Administration>Users and Groups.

No luck - I could read files and open directories, and create directories, but not write to or copy files. Here's a quirk: Last week, I ran into a corollary issue: while I have been able to read files from Mac external USB HDs, I found recently that I was unable to WRITE to any of the ones I tried! The user number was 99, and since I know Mac OSX is in fact a Unix variant I tried creating a user with user number 99.

View files on mac hd in external