Visual Studio always upgrade my solution

I’m upgrading a Visual Studio 2010 solution to a Visual Studio 2012 one. It’s part of a migration of a solution from SharePoint 2010 to 2013 (and there are good details about this here). Annoyingly, though, every time I open the project it says that it has ben upgraded and shows an Upgrade Report. Nothing appears to be modified, but still, it’s shown.

Google didn’t show a lot of help on this, but in the end I decided to simply open the .csproj file and look for some sort of flag about being upgraded. I found the element:

<FileUpgradeFlags>0</FileUpgradeFlags>

so I tried deleting the ‘0’ and reloading the project – and it didn’t show an Upgrade Report. Hurrah. Not sure why I needed to so this, though.

Visual Studio always upgrade my solution