Changing a Managed Metadata Site Column to Allow Multiple Values
We were trying to change an existing Managed Metadata Site Column from allowing single values to allow multiple values. When we did so, we received this error:
/Lists/Projects : Cannot change this column to allow multiple values because it is
currently being indexed.
The error is a little bit misleading, as it might lead you to believe that the list is currently being indexed by search. (At least, that was what my client and I took it to mean.) In fact, the issue is that the column is indexed in the indicated list, which in this case was: /Lists/Projects.
I found a Microsoft KB article (2015261) which explained that “This itself is expected behavior.” The article applies to Microsoft Office SharePoint Portal Server 2003, but the same process fixes the issue in SharePoint 2010 (and therefore, I would expect in SharePoint 2007 as well).
By manually removing the index on the column in the Projects list, we were able to set the Site Column to allow multiple values. Note that multi-select columns in a list cannot be indexed in the list, so there’s a trade off. However, I’ve never had anyone explain clearly what difference adding an index to a list column gives us in the first place.
Adding a list column index will perform better on content queries (e.g.CQWP) that filters on that column, same goes for filtered views. Also, managed metadata navigation, which is kind of a filter, might also require that the list column is indexed.
In checking on how this might be done for my list, I hit this column and went ahead and changed a value of my list from single to multi – it deleted all my metadata from that column. It has cost me quite a bit of time and inconvinience to quite a few people (I’m being polite) I tried as instructed by the MS article to change things back, but all the data is gone.
Brian:
Sorry to hear of your troubles with this. I find it odd that the data would have been deleted going from single to multi, though I would expect it going the other way.
M.
Thanks Marc, what you say makes sense – single to multi shouldn’t give an issue.
Had the same issue today in SP2013 in which several libraries were referenced as being indexed. Instead of manually removing the index on the column, the solution that worked for me was to remove the column from the Managed Metadata Filter Panel via List/Library Settings.