I would argue that "see you later" is the most common English equivalent and should also be accepted.
cuz the translation to this should be "أراكَ/كِ لاحقًا" "Araka/ki Laheqan".
Though one should argue using the word "God" instead of Allah. Unacceptable!
Allah could mean God, So that's fine.
ALLAH is a proper noun so it can't really be translated. Its a name that God has given thyself. The translation of 'The God' would be 'الرب'.
Nevertheless, ALLAH willing should be acceptable as Muslims use this phrase in the English speaking countries.
That is impossible. Because Rabb has is used to refer to those who take care and provide. For reference, the Ayah "Rabbir Hamhumaa kamaa rabbayaanii Sagheera". This indicates that Rabb does not mean God.
The exact translation of ان شاء الله is 'If ALLAH so desires'
So "Until next time, God willing!" is wrong, is it? Well, what a surprise!
Tried to meet this daft machine again with 'until we meet again', though 'see you later' is much better in modern English, but even that is unacceptable?!
theology aside, I have a question about "until next time". I wrote "until THE next time" (there's an "al" in there, after all), and it was marked wrong, but I'm not sure why.