Av säkerhetsskäl har identiteten X (under vilken denna webbtillämpning körs) inte behörighet att skapa SQL Express-databasfilen i underkatalogen App_Data.
Click to search this error in Google
English version
For security reasons, the identity 'X' (under which this web application is running), does not have permissions to create the SQL Express Database file within App_Data subdirectory.
.Net Framework