Suddenly, I was getting these messages when opening an orchestration in BizTalk:
q3bGz

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Microsoft Visual Studio
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The ‘ODPackage’ package did not load correctly.

The problem may have been caused by a configuration change or by the installation of another extension. You can get more information by examining the file ‘C:UsersAdministratorAppDataRoamingMicrosoftVisualStudio11.0ActivityLog.xml’.

Continue to show this error message?
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Yes No
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There are a lot of solutions and suggestions in the web:
http://www.44342.com/biztalk-f20-t14861-p1.htm
http://geekswithblogs.net/synBoogaloo/archive/2007/04/17/111745.aspx
http://jglisson73.wordpress.com/2010/12/27/biztalk-orchestration-will-not-open-in-the-designer/

Of course all these didn’t work… A complete uninstall and install of BizTalk worked shortly. (If you do this, you can easily export and import the BizTalk settings in the configuration tool. Remember to delete the databases..) But then the problem reoccurred again.

In the solution there was an empty solution folder but I already removed it. The trick was: delete the complete solution, then do a get-latest on TFS. No problems again!! Solution worked!

It has to to with empty solution folders of files with no extension, in combination with TFS.