some clients (clonezilla-webdav) rapidly create and delete files;
this fails if copyparty is still hashing the file (usually the case)
and the same thing can probably happen due to antivirus etc
add global-option --rm-retry (volflag rm_retry) specifying
for how long (and how quickly) to keep retrying the deletion
default: retry for 5sec on windows, 0sec (disabled) on everything else
because this is only a problem on windows
3313503ea5