VS2008: Disable asking whether to reload files changed outside the IDE

For VS2008: Tools > Options > Documents > Detect when a file is changed outside the environment

For VS2010/2012/2013/2015: Tools > Options > Environment > Documents > Detect when a file is changed outside the environment

Because a picture paints a thousand words...

In Visual Studio Pro 2012

There is an "Auto-Load changes, if saved" that works.

Tools > Options > Environment > Documents > Detect when a file is changed > Auto-Load changes, if saved