Description:

The error message "Sequence contains more than one matching element"  when opening SQL Multi Script can usually be worked around by re-created the Application.dat file

Steps:

1 - Make sure SQL Multi Script is closed

2 - Using Windows File Explorer go to

%Appdata%\Red Gate\SQL MultiScript 1

3 - Rename Application.dat to Application.dat.bak

4 - Start SQL Multi Script