I just stumbled upon an interesting behavior:

  1. Have a document set:
    • Title: My Special Document Set
  2. Perform a crawl (continuous / incremental crawl)
    • Search returns 1 result.
  3. Rename the document set with different casing: "my special docuMENT SET"
  4. Perform a continuous / incremental crawl
    • Search returns 2 results. One for each case (my special... & My Special...)
    • The DocId managed property is different for both search results
    • The Duplicate Rows are 0 or in other words: Total Rows: 2, Total Rows including Duplicates: 2, so trimduplicates=true does not help, still 2 results.
  5. When I now perform a full crawl, the duplicate entry is removed.

It seems as continuous and incremental crawl do not take care of casing/renames of folders/FileLeafRef and create a duplicate entry for when only the casing of an item is changed. Besides running a full crawl, is there anything else I could do about this?

We're currently evaluating creating an event receiver to trigger CrawlLog.RecrawlDocument on renames but that seems kind of non-standard and weird. The SPListItem.UniqueItemIdis the same for the item so we could actually filter the result set. - weird that duplicate detection doesn't kick in

  • What specific CU/build of SharePoint are you running? This should be fixed in the October 2014 CU.
    – user42509
    May 19, 2015 at 12:31
  • SP2013 SP1 - I just installed May 2015 CU and the problem is fixed. Great!
    – Dennis G
    May 20, 2015 at 8:52

1 Answer 1


This is a SharePoint Bug. It seems to be fixed in the October 2014 CU, I couldn't find any details in any KB article though.

I installed the May 2015 CU on a SharePoint 2013 SP1 patched server and the problem is gone.

  • I am having the same issue with SharePoint 2016 crawed duplicate items. Any idea how to solve this? Jan 31, 2020 at 9:05
  • Also having same issue with SharePoint 2016, currently have to run full crawls to resolve. Any ideas to resolve? Mar 19, 2020 at 19:43
  • I don't think old topics like these will help you. Open up a new question with your specific details.
    – Dennis G
    Mar 22, 2020 at 10:26

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