"Corrupt" ?... How so ?
Please, post the viewer log...
outfit.xml is stored in the per-account settings folder.
For example, under Linux, in
~/.secondlife/firstname_lastname for SL and in
~/.secondlife/firstname_lastname@grid_name for an OpenSim grid.
If you do not want the viewer to restore to your last outfit from this file (which would make sense when you use different viewers), check the "Advanced" -> "Character" -> "Restore outfit from COF" entry (it is checked by default and un-checking it explains what it changes).