I'm trying to setup EXM 3.5 on my Sitecore 8.2u5 instance, which uses a SQL 2014 server. The databases that EXM 3.5 delivers and according to its installation guide you have to attach, seem to be made with SQL 2016, and therefore cannot be attached to a SQL 2014 instance. Anyone knows of a work around? Or is SQL 2014 just not supported for EXM 3.5?
This is most likely a permission problem.
The databases released with EXM follow the Sitecore compatibility table.
Please ensure that the database files are not in read-only mode, and that the user has access to them (you may, as a test, try granting Everyone full access).
As a test, I have just verified that the database files released with EXM 3.5 and 3.5.1 can be attached on SQL Server 2014 (12.0.2000.8)