>Hi,
>
>I have two databases:
>
>"DB" is the live data
>
>"DB Test" is the test database
>
>For testing I am backing up "DB" then restoring it into DB Test, selecting "Overwrite the existing database (WITH REPLACE)".
>
>I am a bit concerned when I check the "Restore as" column, it refers to DB.dmf and ldf. Should I manually change these to "DB Test.mdf" and "DB Test.ldf"? I don't want my live database to be overwritten by this restore.

Yes. Change them. At that point you should not need the Overwrite option unless DB Test already exists.