SCCM migrated to 1511/1602 on new hardawre, client do not re-register with new site

[spgsitsupport]

Migrated SCCM 2012 R2 to new hardware, with new site ID (so I have 2 SCCM setup running concurrently till I retire old server)

 

Existing clients (testing on few) do NOT re-register with new site

 

I can change the site code in client properties, but in ClientIDManagerStartup.log I get:

RegTask: Failed to refresh MP. Error: 0x8000ffff

Anybody any idea how to re-register the client?

Client still "thinks" that MP is still the old one

Site Code is BG1; Management Point is https://old_server.domain.local; MP HTTPS enabled = 1

where BG1 is new site, but MP points still to the old server.

[spgsitsupport]

Re-assignment does not work, but if I uninstall & re-install client, it works fine

ccmsetup.exe /mp:new_server /logon SMSSITECODE=new_site FSP=new_server CCMDEBUGLOGGING=1 CCMLOGLEVEL=0 CCMLOGMAXSIZE=52488000 CCMLOGMAXHISTORY=5 CCMHTTPSSTATE=31 SMSCACHEFLAGS=PERCENTDISKSPACE;NTFSONLY SMSCACHESIZE=15

so why it is not "easily" possible to just re-assign existing client?

[Kops]

I have been re-assigning clients in my site by creating device collections in my new SCCM, then simply doing right click > install client on that collection. There are some options, like if you want to force uninstall the old client first (yes), or always install client (yes), but that has been working well for me so far.

I also posed this question in another thread and a member provided a VBScript that could be run to migrate clients to new sites as well. I haven't tried it yet, but it may be worth a shot.

 

https://www.windows-noob.com/forums/topic/12899-migrate-confimgr-2012-r2-to-new-server/?p=53171

[spgsitsupport]

Been through this script, have long thread going on MS forums, with only a workaround by myself. Seems really like nobody knows...