I'm trying to do a simple buffer around a 4 state state region, but it will not execute. It successfully worked on a different region, but now it wont even show the status bar on the bottom right? It will be unresponsive for what seems like an infinite amount of time until you close ArcMap and then a warning pops up saying that there is some geo-processing going on still. Any ideas?
It's hard to say without seeing your data, but here are some general ideas.
1.) Restart ArcMap and try again
2.) Try running from ArcCatalog
3.) Try buffering with background processing disabled
5.) Try exporting your selected states to a new feature class and buffer that