BUG:
Minecraft Literally will NOT run with an appdata path containing an "!" (exclamation point)

Example:
My user name for my windows machines is "Thats Bananas!" therefore my appdata directory where .minecraft is placed is: C:\Users\Thats Bananas!\AppData\Roaming

OLD Workaround (now broken):
I Created a batch/cmd script to temporarily change the appdata environment variable to a directory that does NOT contain an exclamation point. Then launch Minecraft.exe with the temp appdata location. and Voila all is good. Minecraft would create a new .minecraft folder into my new location, download the game and run. no problems. The newest launcher does not seem to allow this functionality. It pulls the appdata directory from a different value or somehow overrides my environment variable.

Background:
I Purchased Minecraft in April of 2011, this bug has existed since then, but I have always had a work around that was functional. So I never really bothered to enter a bug regarding the !(exclamation point) problem

Prior to the release of your launcher I even had written up my own MC Launcher app in C# that did the same thing, only it worked. I bring this bug to you now because using the latest software I cannot get the .minecraft folder out of C:\Users\Thats Bananas!\AppData\Roaming this problem has rendered minecraft currently unplayable.

I hope that you can either:
1 - Fixed the launcher to properly relocate the .minecraft folder for download and execution
or
2 - Simply fix what ever exception is hanging up the process because there is an exclamation point in the path.