Whenever I want to create a new text file using Windows 7 Explorer’s New ⇨ Text File context-menu entry, I get a file with an uppercase extension. For example instead of
New Text Document.txt, I get
New Text Document.TXT.
HKEY_CLASSES_ROOT and found a key named
.TXT. I renamed it to
.txt and after rebooting, it works as expected. Unfortunately, after a while, it started happening again.