You’re likely here because you have a SharePoint list that contains a multi-line text column with appending enabled. The issue as it presents itself is that your list items are losing the appended column data when someone updates the item. It may be that the appended data is completely gone or that it loses all but the latest entry.
When you first add a “Multiple lines of text” column to a SharePoint list you have the option to enable “Append Changes to Existing Text”. If you don’t already have versioning enabled on the list you’ll get the following dialog box when you click OK to create the column:
I’m not going to go into enabling versioning in this post. The assumption is that you’re seeing the issue in the title because you had versioning enabled on a list and you created a multi-line text column that enabled appending.
What we’ve discovered as the most likely cause is that versioning at some point has now been disabled on this particular SharePoint list. Having version history disabled and then updating a list item will actually overwrite all of the previously appended comments with whatever the last update contained. If it was blank it will blank out the comments.
The underlying issue here is that disabling version history on a list in SharePoint 2010 that has a column that appends text does NOT give a warning. I have yet to test this on SharePoint 2013 to see if the same flaw still exists.
In summary, adding a multi-line text column with appended text to a list and then later disabling version history on said list is something you want to avoid. To resolve the issue simply re-enable version history on the list.