ReadyNas OS6.5.1 on 516 - Cannot create new shares. Error: Cannot get GID for guest

Hi all,

Wonder if anyone can help? :manhappy:

I have a ReadyNAS RNS51600 running OS 6.5.1, I've had this for a few years and all has been working fine. Just recently though I have tried to create a new share only to be greeted with the following error box:

I've checked on the readynas itself and the GID and user guest definitely exist:

root@readynas:/# id guest
uid=99(guest) gid=99(guest) groups=99(guest)

any ideas? this is baffling me and I've worryingly read other psts about resetting back to factory defaults, not an option here with ~12Tb of data on it.

Cheers,

Rich