I just noticed that when I try to use the built in "View As Hex" command it doesn't seem to work. The command was added directly from the list of commands as you can see here:
In preferences the Text plugin does appear enabled:
One thing I did notice, though I'm not sure if it's related, is that the MultiView plugin was disabled, and when I went to click the gear next to it, it says "Viewer DLLs could not be located":
And when I went to add the "Viewers" folder in Program Files containing the DLLs, it wouldn't let me hit OK with it selected for some reason:
It lets me enable the Multiview plugin with the checkbox and save it but it still says the message about DLLs not being located when I hit the gear. Not sure if that's just a red herring or what.
The "View As Hex" command only works in the standalone viewer, not in listers or their preview panes.
But if you're already viewing something with the Text plugin, you can right-click it for the hex option.
(If it's something other than the Text plugin, you can right-click the preview pane's heading and then choose Use Plugin > Text, which will display it as text or hex, depending on the data. If it's text, you can then right-click again for the hex toggle.)
MultiView plugin shouldn't matter here; that's for using the old QuickViewPlus style plugins, which aren't that relevant these days, except as a way to view Office documents without having MS Office.