The error might be due to the syntax problem of the system username.
1. In this case, I request you to go to Hadoop Directory and edit /etc/hadoop/hadoop-env.cmd
2. At the end of the file, you will find set HADOOP_IDENT_STRING=%USERNAME%
3.In this, you can change the file name and rename it, but make sure it does NOT have the space eg.:
I hope this answer helps :)