Traktor pro 2 & m4a compactibility

Hello everyone guys, I am an owner of TRAKTOR KONTROL S2 and TRAKTOR PRO 2

Recently, I moved from Macbook to W7 64bit due to personal reasons

My collection has more than 50 thousand tracks and traktor wont seem able to play these tracks due to their type is .m4a and displays me the following error

"cannot execute BPM detection due to missing transient"

is there anything I can do before converting all those tracks ?

any codec available to install, or a fix or smthin ?

thanks in advance