One of the properties of the Web Part has an incorrect format. Microsoft SharePoint Foundation cannot deserialize the Web Part

Question

I'm replacing the business logic in an existing SharePoint 2013 project. When I deploy the new code I get the error on the subject of a message like was not expected. The markup code is the same before and the old version works.

I tried some solution found on the internet but I cannot resolve this issue.

Error:

I noticed that the first tag in the page is a link type, I commented it and the error changed with the second tag in the page.

I'm replacing the existing business logic using Entity Framework, hope it helps

Answer 1

One of the properties of the Web Part has an incorrect format

This error says your web part properties stored for previous version cannot be deserialized for new version. Maybe you have deleted any web part property in code or changed format. Try deploy old version, clear all property values through interface and than deploy new version.