This option is helluva misleading in my opinion. From my standpoint, when I want only to wipe free space in MFT file instead of wasting time on actual zeroing every cluster of my hard drive, I am looking at a checkbox "Wipe only in MFT" which (or close enough) I found named as "Wipe MFT Free Space". Now I couldn't understand why would it take almost an hour to clean only MFT but I let it pass one or two last times.
This time seeing 2+ hours I had to dig deep into Internet to see that now if you choose this option it actually does the opposite of my expectation! I am quite sure that in the past many years ago I had to set checkbox to dramatically increase the speed of empty space wiping, not uncheck it.
Also it doesn't help that program doesn't tell you that it actually is zeroing every single cluster and just shows expected time instead of "Wiped XGB out of XX GB of free space". Please, consider adding a change which would tell user what actually is going on and a tip how to set it right.
P.S. Oh, the funny part is that after I unchecked that checkbox and ran Cleanup with wiping free space I see that it did not do the job because next files I copy to the drive do not get written from the first empty cluster block but instead of somewhere from the middle of empty space. Where is that simple option to quickly "wipe" free space in MFT only so that it would believe those free blocks are actually empty but not wasting time for actual unnesessary wipe of every cluster?