I had same problem today. I copied vm from windows machine, then exclamation mark appeared.
Vm worked just fine, but I could bear ugly exclamation marked icon.
When I quickviewed that icon, message told me that some encoding problem in vmx file.
vmx's first line looked like .encoding="Windows_cp949_2000" blah blah.
I edited that line of file .encoding="UTF-8".
Problem solved.
After change, vm icon look like above.