I have lost my Compass installation completely. I did not have back ups but could save the Microsoft SQL Server folder. I have now installed Compass and the Database on another computer.
How to restore the Compass Database without having back up files (just with the database files)?
Open the SQL Server Configuration Manager.
Stop the Service of the Database that you want to restore.
Go to the Database Folder on the new computer (something like: C:\Program Files\Microsoft SQL Server\XXX\MSSQL\DATA, whereas XXX stands for the version and name of your SQL Server instance)
Replace all .ldf and .mdf files in this folder by the data you have saved from your old installation. Please make sure that the number and names of the old data files matches the new files.
Go back to the SQL Server Configuration Manager and start again the service of the database.
Open Compass and check whether the recuperation of the DB using the files worked. First time opening the application can take a bit because the DB files are read for the first time.