Update: seem to have cracked it - I un-installed SweetHome 3d and ensured all folders were removed, then deleted the Sweet Home 3D Folder found at: C:\Users\{me}\AppData\Roaming
Reinstalled Sweet Home 3D 3.4 and it's launched first time.

Hope others find this useful as it was driving me nuts ...

Hi,

First off I'd like to say thanks for making this software available - it's a fantastic product however I am now having an issue launching the application.

For the first week the program launched fine, however it then started to take several attempt to launch and now launch's the splash screen ...