In SharePoint 2013 adding Sandboxed solution I got an error as “Unknown exception occurred while executing a SharePoint solution” as shown blow.
By checking the ULS logs, I have found the following text as “An unknown exception occurred while executing a sandboxed code solution request in the worker process.\r\n|0 – userCodeWrapperType.FullName = “Microsoft.SharePoint.UserCode.SPUserCodeWebPartWrapper”
I have checked by changing the application pool identity, checked sandboxed service is running is not. But still I am getting the same error. My current running server is a standalone server with Windows Server 2012, Domain Controller, SQL Server 2012, SharePoint 2013, and Visual Studio 2012.
By digging this into deep, found that there is no fix for this issue, we have to create the new environment. By enabling verbose logging for Sandboxed code solution it will give us temporary fix but not permanent.