GiraffeIT have been investigating a curious issue where no matter what server load is the profile that is loading ( a mandatory windows seven on since you ask ) is taking an age to get “past” preparing your desktop.
We moved the profiles to different servers, we disabled DFS namespaces ( crucially note that DFS replication is strongly advised against being used ) monitored network traffic with wireshark.
The problem wasn’t obvious. There were no RSOP/GPResult errors. All looked fine.
Logons were taking 2m40 under low load and 15minutes(!) under heavy load.
We eventually diagnosed the fault as an errant file filter placed on filescreening. The curious desktop.ini was being screened on the fileserver. Once removed the thin ( 1.7Mb ) mandatory profile loaded quickly.
23seconds now from CTRL-ALT-DEL to working desktop.