I/O exception(5) - *very* slow/incomplete bkup

[dnanian]

The problem -- as documented in the User's Guide -- is that you cannot store an image on a FAT32 volume. FAT32 has a 4GB file size limit, which is why you're seeing it go to 4GB quickly... and then it gets stuck as it tries to copy files, the system fails to extend the image, etc.

So, the way you want to handle this is to either format the external as HFS+ (Mac OS Extended) and write directly to it, or partition it into an HFS+ volume and a FAT32 volume and write to the HFS+ side...

(The logs are inside the settings package. If you open the log (Cmd+L) and then Cmd-click the title bar, it'll show you the full path, and you can select the "Logs" folder there to open it in the Finder.)