Sharepoint\System "User not found"

Look at the code below and if you try to run this code then it will give error while creating a site because sharepoint doesn't find super admin account



 SPSecurity.RunWithElevatedPrivileges(delegate()
            {
                using (SPSite site = new SPSite(url))
                {
                    SPSiteCollection workspaces = site.WebApplication.Sites;
                    using (SPSite workspaceSite = workspaces.Add("URL", "Name", "Description", 1033, "BDR#0", SPContext.Current.Web.CurrentUser.LoginName, SPContext.Current.Web.CurrentUser.Name, SPContext.Current.Web.CurrentUser.Email))
                    {
                        return workspaceSite.ID;
                    }
                }
            });

So the workaround of this problem is to get the default site administrator of current site collection and put it in new site collection


 SPSecurity.RunWithElevatedPrivileges(delegate()
            {
                using (SPSite site = new SPSite(url))
                {
                    SPUser administrator = site.RootWeb.SiteAdministrators[0];
                    SPSiteCollection workspaces = site.WebApplication.Sites;
                    using (SPSite workspaceSite = workspaces.Add("URL", "Name", "Description", 1033, "BDR#0", administrator.LoginName, administrator.Name, administrator.Email))
                    {
                       return workspaceSite.ID;
                    }
                }
            });

BDR#0 is the template Name for document center site. You can use any of the following in site creation process:

ID	Name	Display group
0	GLOBAL#0	Global template
1	STS#0	Team Site
1	STS#1	Blank Site
1	STS#2	Document Workspace
2	MPS#0	Basic Meeting Workspace
2	MPS#1	Blank Meeting Workspace
2	MPS#2	Decision Meeting Workspace
2	MPS#3	Social Meeting Workspace
2	MPS#4	Multipage Meeting Workspace
3	CENTRALADMIN#0	Central Admin Site
4	WIKI#0	Wiki Site
7	BDR#0	Document Center
9	BLOG#0	Blog
15	SGS#0	Group Work Site
16	TENANTADMIN#0	Tenant Admin Site
20	SPS#0	SharePoint Portal Server Site
21	SPSPERS#0	SharePoint Portal Server Personal Space
22	SPSMSITE#0	Personalization Site
30	SPSTOC#0	Contents area Template
31	SPSTOPIC#0	Topic area template
32	SPSNEWS#0	News Site
33	SPSNHOME#0	News Site
34	SPSSITES#0	Site Directory
36	SPSCOMMU#0	Community area template
38	SPSREPORTCENTER#0	Report Center
39	CMSPUBLISHING#0	Publishing Site
40	OSRV#0	Shared Services Administration Site
47	SPSPORTAL#0	Collaboration Portal
50	SRCHCEN#0	Enterprise Search Center
51	PROFILES#0	Profiles
52	BLANKINTERNETCONTAINER#0	Publishing Portal
53	BLANKINTERNET#0	Publishing Site
53	BLANKINTERNET#1	Press Releases Site
53	BLANKINTERNET#2	Publishing Site with Workflow
54	SPSMSITEHOST#0	My Site Host
56	ENTERWIKI#0	Enterprise Wiki
61	visprus#0	Visio Process Repository
90	SRCHCENTERLITE#0	Basic Search Center
90	SRCHCENTERLITE#1	Basic Search Center
2000	SRCHCENTERFAST#0	FAST Search Center
2764	ACCSRV#0	Access Services Site
2764	ACCSRV#1	Assets Web Database
2764	ACCSRV#3	Charitable Contributions Web Database
2764	ACCSRV#4	Contacts Web Database
2764	ACCSRV#6	Issues Web Database
2764	ACCSRV#5	Projects Web Database
3100	PPSMASite#0	PerformancePoint
3200	BICenterSite#0	Business Intelligence Center
14483	OFFILE#0	(obsolete) Records Center
14483	OFFILE#1	Records Center