LSOpenURLsWithRole() failed with error -10810 Can't open 'Install OS X Yosemite.app' I'm trying to install OS X Yosemite through 'Install OS X Yosemite.app' downloaded from the Internet. When I try to open it by double clicking it, nothing happens. When I use the terminal I get the following message:

$ open /Applications/Install\ OS\ X\ Yosemite.app/
LSOpenURLsWithRole() failed with error -10810 for the file /Applications/Install OS X Yosemite.app.
That would seem to imply the executable within the package isn't actually executable. 

Where did you get it from?
If not Apple, I'd leave it well alone. If it was from Apple, try this in Terminal

chmod +x /Applications/Install\ OS\ X\ Yosemite.app/Contents/MacOS/InstallAssistant