Reply To: Login failed In SQL Server 2012
Andrew Jackson ~
Modified: September 10th, 2015 ~ ~ 1 Minute Reading
Login details are stored in the master, so it makes sense that they would be gone if you’ve replaced the master database files.
Do you have a copy of your old master.mdf and .ldf file, or did you overwrite them? If not, you will have to recreate all the logins