Steps to reproduce
Head to v1.5.1
Switch to pre-release 1.5.2
It simply doesn't work, it will remain on 1.5.1
If it helps, rather than being called minecraft.jar, its called 1.5.2.jar
Comments 4
Yes and for some reason after almost a month of 1.5.2 beeing released you're the only one who's having problems updating. So please use the Mojang Support Center for technical support issues.
Old launcher isn't supported anymore please use the new one.