当用户取消文件覆盖时，Excel COMException 0x800A03EC

I have code that saves an excel file to a specific location and filename that cannot be changed by the user. It works fine when the file doesn't exist and saves silently. If the file does already exist and the user selects to overwrite it then it works fine as well. The problem occurs when it already exists and the user cancels the save. This causes the COMException 0x800A03EC to be thrown. Any ideas?I have code that saves an excel file to a speci