File system corrupted?

After an update I see under “files” a different file structure showing directories such as “um5files”, “flash”, etc. These were not visible before, but the problem is that whenever I try to browse files from an external usb pendrive (and even if I format it through RouterOS, load the files on my PC and then connect it back to the router) I cannot see the files at all.

There’s “flash\rw” where it was typically the root file system. I’m in a version that won’t allow to run the older winbox, so I can’t know if this is a “new winbox” deal or if my router is corrupted somehow.

usb1 shows as a directory, usb1-part1 also shows, but no content.

Any clue as to how I could fix this? Thanks