Hi @wangj50 --- we generally don't write up user documents detailing workaround for bugs, we would rather see those bugs fixed up! As a general note, our issue trackers are where we track the status of bugs. Fortunately for you, the issue that was linked to in the post you referenced above has been fixed, and should be available in the next release of QIIME 2 (2017.7). This bug fix removes the need to strip all underscores from sample IDs. Thanks!