Just thought I could save someone some time.... Imagine you are trying to create a SharePoint view, were you want to group by a specific column, but when you go to group-by drop down list, your column does not show up. Chances are that the column you are trying to group by is of type 'multiple lines of text'. Unless you can do some custom dev on this, a quick and simple solution will be to just change its type to 'single line of text', and your column will now appear in the group-by drop down.
Data and Advanced Analytics. Formerly SharePoint.