Could not load file or assembly 'Microsoft.Sharepoint.Sandbox' or one of its dependencies. An attempt was made to load a program with an incorrect format.

In this post we will discuss about how to solve the error message "Could not load file or assembly 'Microsoft.Sharepoint.Sandbox' or one of its dependencies. An attempt was made to load a  program with an incorrect format."

Also you can check out my previous posts on:
- Tutorial on User Profile service application in SharePoint 2013

- Attach event receivers to SharePoint list using PowerShell

- Workflow custom form changes in SharePoint 2013

Error:
While working with SharePoint 2010 with Visual Studio 2010 I got the below error:
Could not load file or assembly 'Microsoft.Sharepoint.Sandbox' or one of its dependencies. An attempt was made to load a program with an incorrect format.

This error came for a Sandboxed solution.

Solution:
Open the Bin folder and Remove the dll from the bin folder.

Now when you debug the error should not come.