Files are shown again after deduplication

Question / Problem

After running a deduplication, when I start the same duplicates search again, the same duplicate files appear and nothing appears to have happened, although the logs show they were deduplicated.

Answer / Solution

In most cases, the reason for this is that Windows is not reporting the amount of hardlinks correctly.

In order to filter out files that were already deduplicated, TreeSize will ignore files that have more than one hard link. For files that are accessed via a network drive, however, there are cases where the amount of hard links is not returned correctly by the operating system, as stated in this article: https://knowledgebase.jam-software.com/7092