FAT32FS

I have an Rpi4B that boots RO 5.28 from a 64GB SD-card. I also have a large Sonnics drive attached via a USB3 port, that puts a SCSI::4 drive icon on the iconbar icon. When I click on it, its name changes to Fat32_4 and the filer opens it as Fat32fs::Fat32_4.$. I use that for most permanent storage. However something has got corrupted. If I open a filer window on certain directory (Fat32_4.$.Test.c) the filenames are all wrong, NetSurf crashes and the mouse ceases to function, so I have to turn off the power. My suspicions lie with the Fat32fs module (v1.54 02 March 2020) whose Count is 39,400 bytes. Can anybody tell me if this is correct? Where would I download a new copy from to get an uncorrupted version? Or can anybody suggest other causes of the filer’s behaviour with the Fat32_4 drive? I suppose the most likely is that the Sonnics drive has a fault on it. I do not think DiscKnight can cope with Fat32fs, so I am not sure what tools are available under RISC OS. Are there any Unix tools for checking such drives?
Help needed.

Over at Jeff Doggett’s site: https://sites.google.com/site/jeffreyadoggett/

You could try dosfsck (part of dosfstools) to check the structure on the external drive.

Fat32fs module (v1.54 02 March 2020) whose Count is 39,400 bytes.

That’s what it is here, so your suspicions may be unfounded.

It looks as if the Sonnics drive is corrupted. Now how to remove as much as I can rescue from it, before reformatting?

DiscKnight only works with native RISC OS Filecore format. If you attach the FAT32 drive to a Linux machine, you can check and fix it using the fsck command (after finding out which device it is and unmounting it).

Thanks.

fsck did the trick.