It appears probably due to usage of some directory while deleting, since after pressing Retry---------------------------
Total Commander
---------------------------
The following files/folders could not be deleted
test\folder1\
test\folder2\
test\folder3\
test\folder4\
test\folder5\
test\folder6\
test\folder7\
test\folder8\
...
Try again?
---------------------------
Retry Cancel
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the dialog re-appears again, but without test\folder1\ line. Pressing Retry over and over till this list is gone leads to getting all this paths removed.
I suggest to add "Retry to all" button to this dialog, so user won't have to press "Retry" for each path in the list.