Windows Installer – The Specified path is too long with subst.

I was testing an installation script (produced by a Visual Studio 2010 set-up project) on a open box virtual machine and was intermittently getting a lovely error message telling me that the ‘specified path is too long’, even though the path that the error message displayed as being incredibly short.

Anyway, I was installing to a subst’ed drive in an attempt to match the clients IT set-up and it seems that the windows installer just doesn’t work well with subst at all. So, to get around the problem I removed the subst’ed drive and instead added another virtual drive to the virtual box machine and everything worked ok.

So I know there are many many reasons for the ‘specified path is too long’ installer error message (most of which have nothing to do with long paths at all!) but one thing is for sure – installing to a subst’ed drive is one cause!