This bug was supposed to be fixed in version 3.6, but maybe you've got some files that are not completely corrupted.
Anyway if you want to clear the files that Sweet Home 3D try to open at program startup, remove the files found in the recovery subfolder of the program private folder.
- under Windows Vista / 7 / 8, this private folder is C:\Users\user\AppData\Roaming\eTeks\Sweet Home 3D,
- under Windows XP and previous versions of Windows, this folder is C:\Documents and Settings\user\Application Data\eTeks\Sweet Home 3D,
- under Mac OS X, it's the subfolder Library/Application Support/eTeks/Sweet Home 3D of your user folder,
- under Linux and other Unix, it's the subfolder .eteks/sweethome3d of your user folder,
- under the portable version, it's the subfolder data of the folder that contains Sweet Home 3D applications.

Under Mac OS X, to ensure you pick the right eTeks folder, you can open a new window in the Finder, select Go > Go To Folder menu item (cmd + Shift + G shortcut), and enter the folder ~/Library/Application Support.

Please, [url=mailto:[email protected]]send me[/url] one of the files you'll removed. It may help me to improve the recovery system.