Default Stuck at Bootanimation with encrypted Phone

Hello everyone,

i have my phone encrypted since some time and never had any problems. i am running cyanogenmod. used all the time just the stable version, no nightlys. yesterday i installed 10.2.1 without any problems. today i got a notification that cm11 snapshot is aviable and wantet to install it. i got an error (Error executing updater binary in zip..) and after that my phone was stuck at the bootlogo. i was able to go back to recovery and could flash 10.2.1 again. but after a few hours i found out that playstore was not working anymore. after playing around it it for a while i decidet its time to do a factory reset and start new.

but after a factory reset now i am stuck at the bootlogo again and get my phone running again.

i tryed to install aokp and got the same error as with the cm11 snapshot

any idea how i could get my phone running again (without loosing the contents of my "SD-Card")?