I use the Steam Mobile App to do various things like supply the steam guard token when logging into the steam website, or for confirming trades.

I have 2 steam accounts, one is a dummy one I use for managing overflow from my main account's backpack and for trading my junk.   Previously I had both accounts loaded onto the Steam Mobile App.

At some stage the Steam Mobile App upgraded.  Recently I needed to trade some stuff from my main to my dummy account and discovered the dummy account isn't in the new Mobile App any more.   I cannot log onto the steam website using the dummy account because it asks for me to use the Steam App to confirm.

No problem, there's the option to add another account to the Steam Mobile App. 

BUT

Under steam guard there is the option to add an account.  So I enter my dummy account user name and pw and it asks me to......

.... use the steam mobile app to confirm.

Wut?   How do I do that if I have not added the account yet?  Until I add the account I cannot confirm it is indeed me trying to add the account.   It's almost like it knows I have steam authenticator for the dummy account somewhere, but hasn't realised it has dropped it from my Steam Mobile App when it upgraded.

Does anyone know how to fix this?

And if not do you know a work around?   Im happy to lose trading for a few weeks, which I think you do if you don't use the authenticator, if it means I can get this up and running again.

All help appreciated.