Sys.WebForms.PageRequestManagerParserErrorException : issue in .NET framework 4.5.2

Hi Team,

We have .NET framework 4.0 web application and opened the solution into visual studio 2015. Build was successful and if we clicked on save button on very first of our application, we are getting below error message.

Throughout the application we are getting below error.(especially during post back of the page).

Error Msg: Sys.WebForms.PageRequestManagerParserErrorException: Themessage received from the server could not be parsed.Commoncauses for this error are when the response is modified by calss to Response.Write(),response filters,HttpModules, or server trace is enabled. Details : Error parsing near 'ect the following:"|e_ButtonImg" src="Im".

We are migrating our application from .NET 4.0(VS2010) to 4.5.2(VS2015- recently  installed ). Although, we changed the target framework to 4.5.2 and build was successful, Application opened successfully in browser after clicking on save button we are getting same issue. Please guide  us how to resolve the above issue.

Note : Regarding this issue i have posted in below link

https://social.msdn.microsoft.com/Forums/vstudio/en-US/feb35063-5923-4d9d-8c6a-57d59e6eb06c/visual-studio-2015-issue?forum=netfxbcl

Thanks much.

Sara