Came across this again today at a client site. They had an InfoPath form published to a form library, but they were not promoting all of the data collected in the form out to the SharePoint library as columns. Since they wanted to do some reporting on the data in the forms, I promoted the columns they needed to the library. BUT...
When I looked at the library and at the promoted fields, there was no data in the fields for the old forms that had already been submitted. Somehow I needed to update all the forms, but I didn't want to open them all up and save them again. (Not being lazy, it's just that there were a lot of forms in this library!)
DO NOT - DO NOT!! - use the "Relink Documents" action on the view menu. It will work to update the forms and the data will show up in the promoted columns, but if you have workflows connected to the form, THEY WILL RUN. (Just sayin'. I've had to send one too many apology emails to massive amounts of people because of this. (One is one too many, believe me.))
The solution is deceptively simple and I don't even know why it works, but it does. In the Ribbon, under the Library Tools, Library tab, in the Connect & Export section, click on Open with Explorer. As the files render in the Explorer window, you will see the icons next to the file names change to the InfoPath icon. Wait for them all to change. If you have a lot of files, you can scroll down to expose the ones that have not changed yet. When all the icons have rendered, shut the Explorer window and refresh your view, you will see the promoted columns contain the data that was in the form.