From this website/link:
I discovered that VHDX file (created by Disk2vhd Utility program) for SBS2011 OS partition can't be bigger than 127GB. Otherwise it may not work at all.
Since I was not successful in migrating physical SBS2011 to a VM in Hyer-V server, I wonder if it was because my VHDX file was bigger than 127GB. In my case, files and folders along with active directory moved over just fine when I started a SBS2011 VM, but client Outlook failed to connect to Exchange Server 2010 even though all exchange server services were running in SERVICES.msc.
I like to know from experts who have migrated a physical SBS2011 to a VM in Hyer-V server if such a limit exists.