adding the solution at the top (explanation below): i switched file managers from caja (the one installed with ubuntu mate) to pcmanfm (the one i use in bodhi and debian lxde) and was able to access the drive as usual.
aaaaand the culprit is…caja, mubuntu’s stock file manager. after reading through Akito’s first few questions again, i wanted to check in mubuntu to see if i could access subdirectories in the terminal. for whatever reason that got me thinking forward just a bit to doing the same in debian next. that train of thought made a brief (mostly non-sequitur) stop in a station apparently labeled “doesn’t debian use pcmanfm like bodhi?”
a quick install later, i was able to access my wd external as i normally do in bodhi. for whatever reason after caja runs into that corrupt bin file, it throws a popup window error and either can’t access (even after i close the popup) the other files on the external or gets caught in a loop as the loading circle just keeps spinning away.
i appreciate everyone who stopped by to offer helpful thoughts and tips. for budgetary reasons i will be sticking with the externals i have for the time being. i will consider reformatting at some point (if that is possible), but as ElectricDandySlider mentioned i will have to juggle some stuff as i don’t have any other externals with that much space.
edit: for whatever reason i am not able to choose this (or any post in this thread) as the solution. any chance one of the other mods can if they see this? i looked in other threads and most (please introduce yourself also does not) have the solution checkbox as a choice. this one does not for me.