This time i wrote this post in english because i think this workaround will be interesting for a lot of people.

Ok the issue is that i tried to access my QNAP Turbo NAS TS-410 over AFP with OS X LION Developer Preview 2 and got a error message like this one above. I couldn’t login with a registered user on my QNAP NAS box. The guest account worked fine but no chance with a registered one.

So i found a solution and explanation at the Apple Developer Forum. Apple disables support for the „DHCAST128“ in OS X 10.7 LION , which is commonly used by NAS boxes. Apple thinks is it insufficiently secure. So all the Vendors must work with Apple for Lion compatibility.

To turn on „DHCAST128“ support please do the following: 1) Launch /Applications/Utilities/Terminal and do:

sudo chmod o+w /Library/Preferences

defaults write /Library/Preferences/com.apple.AppleShareClient afp_host_prefs_version -int 1

Now restart your computer.

2) From Finder, select an AFP server, or use „Connect To…“. This will cause the AFP Client to create the full preferences file

3) Launch Terminal again and do:

sudo defaults write /Library/Preferences/com.apple.AppleShareClient afp_disabled_uams -array „Cleartxt Passwrd“ „MS2.0“ „2-Way Randnum exchange“

sudo chmod o-w /Library/Preferences

Now restart your computer. Note: To add a „DHCAST128“ to the disable list, use

sudo defaults write /Library/Preferences/com.apple.AppleShareClient afp_disabled_uams -array-add „DHCAST128“

I tried it at my OS X LION installation an it worked like a charm. I hope that all the Vendors like QNAP, Synology etc. will patch that in future firmware releases.