On my Mac when I start Arduino 1.0.1 I get an empty sketch (sketch_nov26a) - todays date
If goto Arduino/Sletch/Show Sketch Folder I am shown a folder in /var/folders/7l/hn (etc)/T/untitled (etc)/sketch_nov26a, there are several such paths.
In preferences I see the standard Sketch folder - ~/Documents/Arduino etc.
If I look in preferences.txt there is no entry for a /var/... folder
If I do an ls on the folder it all looks normal (not a link), but OSX finder displays th1.0.1e Sketch with a Parallels - which I have installed and do use, but it is not in use at this moment - marker.
There are several similar sketches so it seems to add one every time I open Arduino.
If I use Arduino 1.0 (newly opened from the Download) the same thing happens.
When in parallels I run Visual Studio 2012 with the Arduino for Visual Studio plugin - so it would appear that there is some interaction going on (I will copy this and post it to their forum as well).
Any ideas/comments will be welcome!