And Parallels (Beta) is the culprit. It turns out that files copied from Windows into a shared folder show up on the Mac with the SetUID bit set. In a directory listing, I get: -rw-r-Sr-- 1 jdaniel jdaniel 13104128 Aug 26 10:38 epson10675.exe I think that is where the S went. Once I fixed it via chmod I can now copy the file. Is there any way in Parallels to control the permissons of files copied from Windows to the Mac? This isn't that big a deal as it is very easy to fix.