I wasn’t aware of this tiny little thing – the filesystem in the file created by a Wubi install can be easily mounted as a loop device.
To do so, just open the Terminal and type the below:
mount <path-to-wubi-root-disk> <path-to-where-it-should-be-mounted> -o loop
This will make the kernel auto detect the filesystem type and try to mount it. Alternatively, if you’re sure of the filesystem type, mention it explicitly
mount -t <fs-type> <path-to-wubi-root-disk> <path-to-where-it-should-be-mounted> -o loop
Would come in very handy if someone were to migrate from Wubi install to a full install, just copy over the /home files and all files saved.