Hi and thanks for kicking this off! I'll look into it in more detail when I have more time.

At a quick glance, the function for getting the drive letters seems pretty low level, could there be a simple crate that does this for us? Hopefully such a crate would also deal with the non-navigable drives.

As you said, the user should be able to reach the drive letter listing by navigating upwards, so I think we will need something in addition to (or instead of) a windows-specific on_go_to_root.

But this is definitely a good starting point! I don't immediately see anything missing from your approach.

I couldn't find a crate to list the drives safely, but here's a different version using the windows-rs crate and the GetLogicalDriveStringsW function, which is a bit more straightforward IMO:

[dependencies]
windows = { version = "0.52", features = ["Win32_Storage_FileSystem"] }

use windows::Win32::Storage::FileSystem::{
    GetLogicalDriveStringsW,
};


let drives: Vec<String> = unsafe {
    let buf_size = GetLogicalDriveStringsW(None) as usize;
    let mut buf = vec![0u16; buf_size];
    let ret = GetLogicalDriveStringsW(Some(buf.as_mut_slice())); // TODO: error handling if ret is 0
    String::from_utf16_lossy(&buf)
	.trim_matches('\0')  // remove both trailing nuls
	.split('\0')
	.map(String::from)
	.collect()
};

I didn't yet have time to think about how exactly to slot this into the app logic.