I have imported about 500 000 tracks from helium 11,
now it needs more than 1 day to cach the albums and it is not finish.
Is that normal?
No, this does not seem correct.
WHich exact version of Helium 12 are you using?
Can you try with the most recent beta to see it it helps?
If not, please contact us over Customer support, support.imploded.com
That sounds way to much in time.
I would suggest you to contact us for further assistance in this case: http://support.imploded.com/