Windows prevents you from changing the case of a word in a filename


ISSUE: cannot rename a file (.doc, .pdf, etc) in Windows if the goal is to change the case of a word; prompt appears requesting permission

RESOLUTION: known issue in Windows Vista and newer, prevents changing ONLY the case of a word in a filename.  For example, cannot change Test.doc to test.doc.  As a workaround, you can rename the file to something completely different, and then back to the name your originally intended (ie: change test.doc to Dog.doc, and then to Test.doc).

Microsoft Knowledge Base article