Had a bit of a nightmate this morning trying to open a web project I haven't accessed for a while. The error VS was giving was a "The http redirect request failed.". Yes.. Very useful VS!!
After doing a little googling, the only advice that was give was to clear out the contents of the bin directory of the project you are trying to open.
Did that, and it worked .. so passing this on to everyone in case you also have a similar experience in the future!