Not consistently finding duplicates - Seeking How To info

[TeejMack]

I've been using Duplicate Cleaner Pro for a while, generally it's great. I have multiple backup copies and am eliminating duplicates to have just 1 copy of all my files. Have been using the Same Content match, and it typically gets a VERY high percentage. After that have been using the same filename, extension, size and created or modified date (+/- 2 hours for time shifts). It seems like the amount of files DCP is matching as duplicates over time has gone down. But no idea how that is even possible.

• When I look at the files DCP doesn't match, their properties are EXACTLY the same (name, extension, file created and modified dates, total # of bytes, etc). So the More Duplicate Options should find these even if there is some difference in the Same Content match.
  I've tried Run as Administrator, doesn't seem to change things.
  I have noticed that some are hidden or read-only files, so change those settings to be off. That helps get some more of the matches.
  Is there some limit on the total gigs or number of files DCP can match? Some of these folders are 200+ Gb in size.

These are pretty vanilla multiple backups of the same source at different times, so DCP should be able to see them as duplicates to delete. But, it's leaving behind gigs of files that should get auto-deleted. ANY advice PLEASE? Feels like there are some settings I'm just not getting right.

I did try another de-dupl tool, and it found a ton of dupl I'm trying to match out. But, frankly nowhere near the quality of interface and toolset as DCP. So, I dont want to use that tool or other tools. I really want to figure out what the gap is in how I'm using Duplicate Cleaner Pro!

[DigitalVolcano]

Try not including the Created Date in your criteria - it can vary if files are copied around.

With some files (usually images and docs) the content can get changed by other programs changing metadata within them (i.e. opening a document in Word, or having an image program catalogue your pictures), even if they may appear identical.

[DigitalVolcano]

Also, you can check that the files are being read correctly by adding the Unique tab and checking that the unmatched files at least turn up here with a hash.