When using the Update-Database -Verbose update the database, in appsettings.json configuration file has been modified for the new connection string, but when using the command to update the database connection is still before the database.
Later, when the code moves to a new computer, use the command again to update the database, amazing scene took place
IIS when updating the database actually need to access the release of the temporary storage folder, then you understand why change a database connection address before connecting to the database using still or updated.
Then I put the D: \ IIS \ SSCore release of deleted files, use the command to update the database will be successful again.
Update-Database -Verbose principle under study.