Sorry, not handheld.dll, it's called "hh_portable.dll" and it's in Program Files (x86)\J River\Media Center 17\Plugins.
I've not noticed any side effects by doing this, but I can imagine it's not officially sanctioned advice, and it will likely prevent MC from detecting other non-Apple devices also.
The plot thickens.
Note my prior post asking if I was in the right place to do the 'right click' to 'Remove & Ignore' the iPod. The only place I could see the iPod was under Explorer.
Now I renamed hh_portable.dll and the iPod shows up under devices and under Explorer. Under devices I can do the 'right click' to 'Remove & Ignore' the iPod. If I choose 'Remove & Ignore' the iPod disappears, but it comes back again after I restart MC. I guess this is because I renamed hh_portable.dll.
After renaming hh_portable.dll I no longer get the info message telling me my iPod cannot be properly identified.
So my guess is there is a problem with hh_portable.dll. It should be checking to see if the device was marked as 'Remove & Ignore' and if so it should no longer try to identify it and produce the message I see.
In any case I have a workaround. Thanks for that prod