Could not load file or assembly after upgrading DevExpress

I've been tearing my hair out over this one, and hopefully it'll be something simple that I'm too thick to work out for myself.

We've got a ASP.NET website (IIS7.5, Server 2008R2) that uses the wonderful DevExpress ASP modules. All was working fine until I had the bright idea of upgrading the modules from 10.1.4 to 10.1.7. Ever since, the site throws intermittent but regular errors that it:

Could not load file or assembly 'DevExpress.Data.v10.1, Version=10.1.4.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

All the .aspx files have similar register tags, e.g.:

<%@ Register assembly="DevExpress.Web.ASPxEditors.v10.1" namespace="DevExpress.Web.ASPxEditors" tagprefix="dx" %>

I updated the VS2010 project using DevExpress's own upgrader utility. There is no reference to v10.1.4 anywhere in the code - I've checked the .aspx files, web.config etc - and the web server has all the latest .DLL's on too. I've even moved the site to a complete new, virgin server, yet the error still occurs. Specifying the subversion number and public key in the register tag doesn't make any different.

I've iisreset'd, cleared out temporary files, rebooted etc, all to no avail. The r开发者_开发知识库eally frustrating thing is the error isn't reproducible - sometimes it happens, sometimes it doesn't. Can anyone help me out?

In the solutionExplorer: switched to the File View and changed

CopyLocal = true 

for all DevExpress assemblies both in the Server and ServerGenerated projects. It resolves the issue for me. Could you please try it and let me know if that helps?

Please make certain that the application's bin folder does not contain our old assemblies. Also, search your project for '10.1.4.0' substring and make sure that this string does not appear. If this does not help, you must be sure that your application does not reference a dll which references our old assemblies or which is residing in the bin folder. Finally, a good idea is to clear the Temporary ASP.NET Files Folder ("C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files")... I hope, this will be helpful.