asp.net - Sitecore: argument out of range when page editor is enabled -

the goal right run sitecore page editor without issues. error comes following url:

http://localhost/sitecore/shell/applications/webedit/webeditribbon.aspx?db=master&id={guid}&la=en&vs=1&url=%2f&mode=edit&sc_pagesite=website&trf=%2ftemp%2fdiagnostics%2ftrace_{guid}.xml&prf=%2ftemp%2fdiagnostics%2fprofile_{guid}.xml&dev={guid} 

i'm getting exception when open page page editor enabled:

16028 13:57:46 error application error. exception: system.web.httpunhandledexception message: exception of type 'system.web.httpunhandledexception' thrown. source: system.web    @ system.web.ui.page.handleerror(exception e)    @ system.web.ui.page.processrequestmain(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint)    @ system.web.ui.page.processrequest(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint)    @ system.web.ui.page.processrequest()    @ system.web.ui.page.processrequest(httpcontext context)    @ asp.sitecore_shell_applications_webedit_webeditribbon_aspx.processrequest(httpcontext context) in c:\windows\microsoft.net\framework64\v4.0.30319\temporary asp.net files\root\3d565cb3\44f479ba\app_web_pyaedh12.0.cs:line 0    @ system.web.httpapplication.callhandlerexecutionstep.system.web.httpapplication.iexecutionstep.execute()    @ system.web.httpapplication.executestep(iexecutionstep step, boolean& completedsynchronously)  nested exception  exception: system.reflection.targetinvocationexception message: exception has been thrown target of invocation. source: mscorlib    @ system.runtimemethodhandle.invokemethod(object target, object[] arguments, signature sig, boolean constructor)    @ system.reflection.runtimemethodinfo.unsafeinvokeinternal(object obj, object[] parameters, object[] arguments)    @ system.reflection.runtimemethodinfo.invoke(object obj, bindingflags invokeattr, binder binder, object[] parameters, cultureinfo culture)    @ sitecore.reflection.reflectionutil.callmethod(type type, object obj, string methodname, boolean includenonpublic, boolean includeinherited, boolean includestatic, object[] parameters)    @ sitecore.web.ui.sheer.clientpage.onload(eventargs e)    @ system.web.ui.control.loadrecursive()    @ system.web.ui.page.processrequestmain(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint)  nested exception  exception: system.argumentoutofrangeexception message: startindex cannot larger length of string. parameter name: startindex source: mscorlib    @ system.string.substring(int32 startindex, int32 length)    @ sitecore.links.linkprovider.linkbuilder.getitempathelement(item item, siteinfo site)    @ sitecore.links.linkprovider.linkbuilder.builditemurl(item item)    @ sitecore.links.linkprovider.getitemurl(item item, urloptions options)    @ sitecore.providers.linkprovider.getitemurl(item item, urloptions options)    @ sitecore.web.webeditutil.getitemurl(item item)    @ sitecore.shell.applications.webedit.webeditribbonform.rendertreecrumbgo(htmltextwriter output, item item)    @ sitecore.shell.applications.webedit.webeditribbonform.rendertreecrumb(item item)    @ sitecore.shell.applications.webedit.webeditribbonform.onload(eventargs e) 

the page renders fine when page editor disabled.

running versions:

• sitecore 7.2.
• asp.net mvc 5.2.3 (also tried 5.1.3).

i have tried removing that's related sitecore in layouts/renderings, error still occurs. realize can impossible figure out what's going on without seeing configuration files, here's hoping have stumbled onto error before!

thanks!

the issue rootpath attribute. appears cannot 2 levels below /sitecore/content. when changed /sitecore/content/foo/bar /sitecore/content/foo worked again. sitecore veteran can explain why is!