Who knows how long it will take MtGox to fix this issue approximately?
Well, if MtGox doesn't admit it's their fault and not Bitcoin's, never.
They already made their bed by blaming Bitcoin and took the stand that they will not reopen withdrawals till the Bitcoin devs fix the problem. A problem that is not actually a problem, that the bitcoin devs notified everyone about over 3 years ago, and doesn't affect wallets running proper code. It's not Bitcoin's problem that MtGox made up their own hodgepodge of crap code that doesn't work right.
It's basically just an excuse setting up Bitcoin as the reason why MtGox fails so they can play innocent in the face of all MtGox customer loosing everything.
So, yeah, never.