Ok, after some more experimentation, I have tracked it to the following:
I have installed a basic setup, all updates, joined to the domain.
I then push my antivirus (avast for education)
then I reboot the machine, and login.
If Thunderbird is installed on the machine, I get an error on login
Faulting application name: rundll32.exe, version: 6.1.7600.16385, time stamp: 0x4a5bc637
Faulting module name: MSVCR90.dll, version: 9.0.30729.6161, time stamp: 0x4dace5b9
Exception code: 0xc0000417
Fault offset: 0x000311d9
Faulting process id: 0xab0
Faulting application start time: 0x01d0b8cfa5af2121
Faulting application path: C:\Windows\SysWOW64\rundll32.exe
Faulting module path: C:\Windows\WinSxS\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.6161_none_50934f2ebcb7eb57\MSVCR90.dll
Report Id: efedb0c8-24c2-11e5-9354-b8ac6f9077d0
If thunderbird is not installed, I do not get the error.
If I remove thunderbird, I do not get the error.
If roaming profiles are set for a user, or gpedit is set to only allow local profiles, I only get the error on the first login for a user... I don't get it on subsequent logons.
Any suggestions? I don't want local profiles for lab machines, or roaming profiles for students...