Windows server 2012R2 Windows server 2003 | Share access issues after you followed up DFS BPA results

Yesterday I walked into an issue that windows 2003 servers and XP systems weren’t able to connect to a network share located on a Windows server 2012 R2.
I ran the DFS BPA on the Windows server 2012R2 and saw the following message.
Warning Srv.sys should be running.

Well I thought I’ve to look how to solve this warning. After looking on the internet I saw the following forum post: http://social.technet.microsoft.com/Forums/windowsserver/en-US/a5428d04-2a11-4d9a-93cf-56cfa56bbec2/windows-server-2012-r2-bpa-issue?forum=winservermanager
In this forum they wrote:

To get rid of the message you need to change the following registry key. (from option 2 to option 3)
Start REG_DWORD value should be set to 3 (instead of 2) in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv registry key

Well as I know now. When you change this setting on your Windows server 2012R2, you will get rid of the message. If you don’t reboot the server there is no problem with accessing shares from a windows server 2003 to a windows server 2012R2. However when you reboot your windows server 2012, the registry will be activated and now the issues starts. You won’t be able to connect to windows server 2012 shares from any windows 2003 server and you get an error that you can’t access they share / you don’t have permission even you have permission to access.
SO MY ADVICE: DO NOT CHANGE THIS SETTING IN ANY CASE WHEN YOU ARE RUNNING MINIMAL 1 WINDOWS SERVER 2003 IN YOUR DOMAIN!!!