Hi all,
Ive been using Eagle for a couple of years now but this is the first time i came actross this issue.
I tend to manually route critical nets and power and then let the autorouter do the rest.
What is happening recently is that although autorouter finishes giving 100% complete, i then find a couple of air wires still unrouted! They are listed under the statistics function and can be seen on the board too.
Anyone knows why?
Then it thinks it can simply not route them 
Best not to use autoroute. Even though it's smarter then it used to be it still can't do as fine job as humans can and tend to make a mess of it.
A great deal of the problem is then you, as a human, might get new insight in the layout and move some components to a more logical location. The autorouter isn't that smart.
So the best boards are just hand routed
Yes i know that manual routng gives best results. I manually route 80% of the nets but with a dense pcb, it then gets too difficult.
The question however remains , why it shows 100% routed when there are still unrouted wires.
Does it have something to do with the latest version 7.x.z?
Then get better at it 
If you find it hard it's even harder for the autorouter. Especially after you router 80% already.
I must say it's been a while since I did some autoroute tests on Eagle (mainly because I'm a KiCad user), but like I said, I think it tells you the autoroute is 100% complete which is not the same as it routed 100% of the wires. I think it finds it can't route any more wires thus it finds it job complete.
Give it a shot on an earlier version.. (6.x or something)
See if its just a 'bug' in the newest version... although I would imagine the community would been in an uproar if that was the case.
Maybe they round 99.7% upto 100 ? Are there a large number of nets?
why it shows 100% routed when there are still unrouted wires.
I've noticed that the "new" (7.x) autorouter will apparently leave some power pins unrouted, thinking that they care connected to a polygon (but the polygon has been "broken up" and no longer has full connectivity.) If that is what you're seeing, you should do the autorouting before you create the power polygons.
I've noticed that the "new" (7.x) autorouter will apparently leave some power pins unrouted, thinking that they care connected to a polygon (but the polygon has been "broken up" and no longer has full connectivity.) If that is what you're seeing, you should do the autorouting before you create the power polygons.
Ok... I will give it a try...
Maybe they round 99.7% upto 100 ? Are there a large number of nets?
Running the AR with minor component placement changes leaves behind from 1 to 4 nets max.
Just as a FYI - Autodesk purchased Eagle a while back and starting with the new version 8, it is a subscription model (you pay a monthly ransom or it quits working). Version 7.7 is the latest you can get (not sure if you can still get it) that is the old model where you get a license file and it works. Bad news for us Eagle fans ... another one bites the dust. 