From my first visit on this site, I have see many, maybe tens of questions that ask about "Why does my /testfor command output an error", but each one is slightly different and asks about the issue of that one person. For example this: /testfor @p[score_state=1,score_state_min=1] doesn't work!
doesn't work! Why?
It returns this:
The entity UUID provided is in an invalid format
How can I fix this?
There have been many, really many questions about a simmilar what-wrong-with-this-testfor-command questions (a 2-minute
search look found me this: 1, 2) which should be closed as a duplicate, if of course there was one question that would unify all the questions. Every single one of them is one of the problems listed here:
Why does the /testfor command I have always output an error (not listed below)?
Why does the /testfor command I have always output the entity UUID is an invalid format?
Why does the same /testfor command sometimes output the entity UUID is an invalid format instead of found [x] and sometimes not?
Why does the /testfor command not output anything?
So I decided to put all of these into one single Q&A, so that all the questions can be unified: Why does testfor sometimes output an error?
Can all the questions (that haven't been auto-deleted meanwhile) be closed as a duplicate of this one, that covers all the possible errors with /testfor?