Recently, Sandra (my SharePointBuddy) and I built a peer-to-peer recognition site on SharePoint, and it’s really cool. However, we had a couple scenarios where the notification workflow would error out with the following message:
The workflow could not update the item, possibly because one or more columns for the item require a different type of information.
If you’ve run into this issue and done any research, you know that there is no set answer for how to resolve it. Furthermore, many of the answers are “I did this and it started working again, but I don’t know why.” And of course, none of these answers addressed our problem.
After a few days of trying to figure out the “why” behind our particular variation of this, we finally stumbled across the issue.
The recipient of this particular “High Five” had a regular and a test AD account. Unlike most of the test account scenarios, his test account had his regular name with all the associated data fields filled in. When the workflow got to a point where it was trying to build a new list item, we were using the “Display Name” variation of the Recipient People Picker field for the email address. Unfortunately, the Display Name for this person’s account was not unique, so SharePoint Designer was choking on a multi-value data field that was only supposed to be a single-value occurrence.
Once we figured that out, we changed all the usages of that field to use the Login Name (which *was* unique), and then the workflow worked just fine.
I put this out here so that anyone trawling for an answer has at least one more option to choose from…
SharePoint Duffbert 
Umm yes! I deal with this way too often. Everyone at our company has multiple accounts it seems. I dont think anyone thought about the impact to sharepoint when doing creating the AD this way. As standard practice, we use workflow to “loop” through accounts until the right one is found. Its annoying. Also, yesterday I ran into an account that could assign a “to-do” task just fine but it would not send a notification. Solution? Set a variable to the user’s email address and send the notification to the variable. Sometimes its just picky for no good reason!!
PS – love your blog and read it often! Just the other day, I used your “why wont my datasheet view allow editing of a field” article. Thank you and miss working with you!!!
Awww… thanks! Miss you too.