Help- Wierd Date Format since install

[ductapehondo]

Hey all,
Since installing Office2011 my Excel and Outlook date format has defaulted to the following format:
04M12M2011 (Excel) and 12 A2011 (Outlook)
This goes for:
a) manually input data
b)data copy/pasted from other files (created prior to Office 2011, pulled off the internet, etc)
c) files opened that were created in previous versions

When attempting to reformat (in excel) to a more standard form (i.e. 12-Apr-11 or 04/12/2011) the system:
a) thinks its 4-Dec-11 or 12/04/2011
b) does not allow me to reformat at all

This is really becoming a pain.
Any ideas / suggestions?

Thanks,
-EC

 

[ductapehondo]

Additional info:
I've updated system preferences date format Short, Med, Long to be all the same (i.e. 4 Jan 11), but that has not helped.
When I'm in Excel the default Date format for the cell is like this 04M12M2011 and I have to try and manually change it. Sometimes Excel allows me to change to 4-Jan-11, other times it will change to the numerical equivalent (i.e. 40880) when I try to use the quick format tool (paint brush icon), or it just does not allow me to change at all.
When cutting and pasting from a web page or a CSV import (i.e. my credit card statement) Excel formats the dates inconsistently (some are of General format 1/4/2011 and won't let me change format) and others are of Date format 04M12M2011 with the issue described above).
Still can't figure it out...

 

[ductapehondo]

Figured it out!
The system preferences format was set to Custom even before I tried to set the Short, Med, Long date formats. Changing it to US did the trick!
Thanks.