Hi my old elicenser had a crack on it, so I got a new one, what I want to know is, can I let my friend use the old one, he just bought Cubase 8.5 but he needs a dongle.
Yes. Just de-register it in your MySteinberg account then he can register it in his account.
Tried that the dongle is registered to him now, but my activation code for my Cubase 8.5 is still coming up, when I try to register his new copy
So are you trying to register HIS copy of Cubase on YOUR MySteinberg account?
No, he has his own account, he recently upgraded to Cubase 8.5 from Cubase elements, now he needs a dongle, I gave him my old one, which has nothing on it, so it appears, but when I try to register his code, it shows my code still there, but when you bring up the dongles content on the e-licenser control it’s empty
Did you install both eLicensers on your computer and transfer the license to your new one as per the procedure in the link?
Take a look. Especially the “Transfering licenses” section.
Regards. 
Thanks, but I already Transferred my data to the new dongle before I gave it to him, and the dongle is empty shows no data, but when I log into his account and try to use his activation code it fails because my code shows up still on the dongle