How to find non duplicate files ?

[Korrigan]

All my data are copied in a backup folder, in order for me to practice and clean up without deleting, for now, any of the original data.
And I have noticed that during the copy ONE file was not copied. Lucky enough for me to know which file is missing in the new (backup) folder.
I wanted to check if AllDup could help me finding it in case, in a similar situation I wouldn't know the missing one.

So performed several searches but unfortunately none managed to spot the missing file.
Here is the search I thought would have the best chances to succeed:

• I've selected both folder (Orignal & Copy) as source folders,
  Search method, in this case is only on the file name (that's the quickest and simplest)
  And for the search option "show only files WITHOUT duplicates at the search results" I thougt that would be the key
  
  For the compare method, I thought that selecting "compare only files between different source folders" would reduce the number of comparisons and still bring me the missing file, but this was not the case.

Regardless of the compare method selected, I always end-up with ALL files listed as result of the search!
I've doubled and tripled checked, the search option "show only files WITHOUT duplicates at the search results" is properly selected and repeated in the search log.

I would be so grateful if someone could help me setting a proper search to find the missing (not copied) files.

THOUSAND THANKS IN ADVANCE

In case it could help, here is the log file of my latest search:

09/02/19 12:59:09 AM - AllDup 4.4.3
09/02/19 12:59:09 AM - Search Method: File name
09/02/19 12:59:09 AM - 1.Source folder: C:\Users\Jipe\Documents\2012 1 file missing\07_2012 1 file missing
09/02/19 12:59:09 AM - 2.Source folder: F:\2012\07_2012
09/02/19 12:59:09 AM - Option: Compare only files between different source folders
09/02/19 12:59:09 AM - File size filter activated: smaller than 5 KB
09/02/19 12:59:09 AM - Determine file count of all source folders...
09/02/19 12:59:09 AM - File count: 9,217
09/02/19 12:59:09 AM - Scan: C:\Users\Jipe\Documents\2012 1 file missing\07_2012 1 file missing
09/02/19 12:59:09 AM - Files filtered: 2,278
09/02/19 12:59:09 AM - Scan: F:\2012\07_2012
09/02/19 12:59:09 AM - Files filtered: 2,278
09/02/19 12:59:10 AM - Found 2331 files without duplicates.
09/02/19 12:59:10 AM - Elapsed time: 00:00:00

There should be only one, not 2331...

[Administrator]

This problem is already fixed and will be available with the next update.