Pi B+ and Volumio 1.41

I have Raspberry Pi B+ and IQAudio Dac+.

(I also have two other Pi Bs with Dac cards which work fine).

So far I have managed to get the DAC working and can play web Radio. I now want to mount NAS volumes for my music. I have tried one using the same instructions which work successfully with my Pi Bs/Volumio 1.4/1.41 and … nothing. I manage to get back to library once from the UI and the Nas mount showed as failed. I rebooted (and have done a few times) but now, the only UI working is Main, Credits and Turn off. Trying Library, Playback, Network, or System results in constant 'waiting for [ip address]. Main Page continues to work and I can play web radio.

I’m guess that it is ‘stuck’ trying to mount the NAS drive.

EDIT

I have a NAS mount which is shown as incorrect (though it has parameters which work on my other PiDac players) which will not be removed by clicking on ‘Remove this mount’. Switching back to the main screen throws the 'mount point deleted, update in process message. But then the Library, Playback, Network and System menus are unresponsive (occassionally throwing a 404 error). Rebooting the device and going into library shows the ‘failed’ NAS mount still there.

How to proceed?