The option Detect only duplicates from different source folders can be useful, but it is implemented inefficiently. Currently what it does is to wait until all files have been scanned as normal, then filter out the results. This means that a lot of unnecessary comparisons are done. Instead, the option should be used to reduce the number of comparisons.
For example, say that all the files below are identical:
Code: Select all
C:\
A\
1.txt
2.txt
B\
a.txt
b.txt
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1.txt - 2.txt
1.txt - a.txt
1.txt - b.txt
2.txt - a.txt
2.txt - b.txt
a.txt - b.txt
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1.txt - a.txt
1.txt - b.txt
2.txt - a.txt
2.txt - b.txt
Files from the same folder are being compared even though the separate sources option is selected: