WinDirStat seems to have an issue with VERY long filenames (as in recursive directories). So I found another utility that is very similar to WinDirStat which could handle the long filenames (so long that Windows will not delete them nor recycle them).
I love WinDirStat, so I am not going to be brash about competitive products, but I DO SINCERELY HOPE this gets fixed soon. If you want more info, you might search SevenForums.com. Thanks guys, LOVE your product despite the bug.
EU ENCONTREI! Se voc? est? procurando isso de 2015 em diante, saiba que depois de revirar a internet eu achei a real solu??o. Esses arquivos escondidos realmente v?m do nosso querido Windows, e n?o s?o vis?veis nem habilitando a bendita op??o de mostrar pastas ocultas. Bom, vamos l?.
WDS tells: 8,4GB unknown, System Volume Information 0GB.
SpaceSniffer tells: System Volume Information 13,4GB and lists files and filedates.
TreeSize Free tells: SVI 13GB and lists files and filedates.
These are broken files being created in the last days by bad java apps.
I deleted all .BLF and .REGTRANS-MS files in c:\windows\system32\config and suddenly all unknown were gone. Got back over 100 Gbyte. Great and thanks for the advice. However unknown are slowly coming back? /Arne
I found the reason for my 350gb of unknown. it was windows backups. I highly recommend these steps for cleaning your pc, they really helped me (one of them is WDS).
just noticed that my link didnt get inputed. here it is in plain text
-ways-to-free-up-hard-disk-space-on-windows/