When the path of a portable installation of 010 Editor changes, the Help Viewer becomes empty. This is only fixable by deleting %USERPROFILE%\AppData\Local\SweetScape\010 Editor - Help Viewer. Ideally, the Help Viewer settings should also be stored alongside the portable installation of 010 Editor.
Yes, you are correct that the portable version can get confused in this case. We’ll try to get this fixed up in our next release.
Graeme
SweetScape Software