The INSTALLSHAREDWOWDIR command line value is not valid.
I was recently making some changes to my laptop setup and installing SQL Server 2008R2 and SQL Server 2012 directly on the computer rather than on my VM. In the case of my setup I had already installed the client tools for 2008R2 and 2012 on my laptop. So in this instance I was simply adding the rest of the SQL tools (IS, RS, AS, BIDS, etc).
Much to my surprise when I went to install 2008R2 onto my laptop I ended up with a strange error message:
The message says there are validation errors on this page and the actual error message reads The INSTALLSHAREDWOWDIR command line value is not valid. Please ensure the specified is… and I can’t remember the rest of it now that I have gotten around to writing this.
If you do some searching online for that error message there are a bunch of random fixes ranging from don’t change the share feature directory, leave it default (which I had left default so that option was out) to installing a hotfix to modifying the registry. I think I tried just about everything I could find with no luck.
Then it dawned on me, that directory already exists on my computer (C:Program Files (x85)Microsoft SQL Server) because I have the client tools installed. Long story short, the only thing that allowed me to continue was to first uninstall the client for both 2008R2 and 2012. I also had some other SQL pieces in there too such as CLR types and the connectivity SDK (for some unknown reason) which I had to remove as well before having any level of success. This left the directory mentioned above still hanging around empty on the file system. Second I had to manually delete the existing directory. The install then completed successfully and I have not had a single issue since.
If you are having the same issue try checking to see if the client tools are already installed. If so, remove them and try again. It just might save you some time and headache by starting fresh.