I asked precisely the same question with LR 3.6 on
That was on my previous computer with Win XP.
Now with Windows 7, on a completely new workstation I have exactly the same issue: When I start LR and select the catalog, everything works as usual. But when I double click on the *.lrcat file, or select one in windows the following happens: Lightroom tries to install itself! !!!!
When I click on cancel, an error 1706 appears, "no valid source could be be foundfor product LR 4.1 64bit, the windows installer cannot proceed."
To go ahead of an obvious question: the file type lrcat seem to be associated with the 64 bit Lightroom:
Has someone a clue what might be happening? I checken what I know about file type assiciations, everything seem as usual pointing by the lightroom.exe binary.
I see the same, Open in Lightroom is the standard action.
The full list of file types served by Lightroom is:
Maybe the reason is that LR is not installed at the std location?
I install to drive E: (extras) directory E:\Foto\Adobe\Lightroom etc.
All my photo stuff is on E:\Foto, and similarly other applications are grouped in their respective root directory.