An error occurred while getting default signature - could not load file or assembly 'Mono.CSharp...'
The below error is usually associated with the upgrade of BrandMail, and results when files have not been correctly overridden during the upgrade process:
In order to rectify, please:
1. Locate the BrandMail Bin folder and DELETE it:
2. Do a fresh install of BrandMail and the problem will be corrected.