Currently a client as 2003 DC and we are migrating them to a 2008R2 on a 2012 Hyper-V Host. They have a handful of roaming profiles - but with the usual setup - i.e. the only permissions on the actual roaming profile folders i.e. username.v2 are SYSTEM (full control) and the actual user (Full control) - I had to take ownership as an admin to actually see these permissions. Basically as per:
http://technet.microsoft.com/en-us/library/cc737633(WS.10).aspx
How can I migrate these across as I have no permissions over them as administrator, can I just do a straight robocopy and then re-point the Profile location attribute in AD to the new location? (obviously configuring share permissions on folder on new server)
I got round this with PSEXEC
On the server that currently stores your profiles bring up an administrative command prompt and run
This gets you into Session 0, effectively running as the local system account, at which point you have the ability to do what you wish with these accounts. I chose to use XCOPY
Xcopy . \newserver\share\ /E /I
You can use the /X switch to preserve the permissions. I chose to leave that off and separately script the permissions to allow access for server admins without having to mess about elevating Explorer or using explorer alternatives.
Once the profiles are across then its just a case of, as you say, pointing AD profiles at the new share\folder.
I did a migration like this during the logon of the user. Don't forget that you want to migrate the registry keys as well as the files. For that you can use the procedure in this blogpost. http://blog.raido.be/?p=297 (it talks about AppSense, but this will work without AppSense also. just use the copy command and the reg.exe command during user logon.