This problem is resolved.But the issue was silly and was nothing to do with
'multiple occurrences',it was a file path issue so instead of *mongoimport
-d test -c articles --type json --file** D:\Projects\Xurch\Parsely
data\articles_split.json.01\articles_split.json* when I ran *mongoimport -d
test -c articles --type json --file "D:\Projects\Xurch\P**arsely
data\articles_split.json.01\articles_split.json".*It ran successfully,silly
issue.Learning is at times MongoDB gives misleading error message which has
nothing to do with cause of error.