Today a question was asked on Writing. Five users voted to close as off-topic, belongs on another site (English, a defined migration path for us). The question shows as on hold, off-topic with no migration link. Somebody asked about it on meta, so as a moderator I tried to see what had happened.

My first stop was the (moderator) timeline, which shows the five close votes, the post being locked, and then the post being unlocked. That's consistent with it having been migrated and then the other site closing the question; rejected migrations bounce back. I wanted to look at the question on the other site to confirm that (and see the close reason) -- and found no link, anywhere: not in the post revision history (for which I had to construct the URL by hand), not in the timeline, and (as a presumed bounce-back) no longer on the question itself.

I then looked for the question, first using search and then using "newest questions", and didn't find it. Did the other site not only close but delete the question in the last 8 hours? Maybe, but that didn't sound likely.

So I went back to the timeline, where I then noticed that the timestamps for the lock and unlock events are identical. That sounds like a failed migration, but the only reason I know of for that is the user being suspended or question-blocked on the target site. This user has no account on the other site, so it's not that. The only other thing I could think of was that maybe the IP address became blocked between the time the question was asked and when the migration was attempted -- but no, the IP isn't blocked.

What happened here? Did I miss something in the available tools that could have told me? If not, is there anything that can be improved in the tools that would have made this easier to figure out?

  • @Sonic we don't know whether the question was migrated, so saying it wasn't migrated isn't correct. It could have been migrated and then rejected, though the timestamps make that unlikely. Nov 18, 2018 at 2:45

1 Answer 1


The users voted to migrate the question, but it was blocked by the system because the sole tag on the question, , doesn't exist on the target site.

When normal users vote to migrate a question, the question must use at least one tag that exists on the destination site, or else it will be blocked by the system in the same manner as if the post author is banned. However, you probably forgot about this rule because moderator migrations are exempt from it, with the target question getting the tag .

If you reopen and re-migrate the question, it will work, since you're a moderator.

(Another situation where this may happen is if the author or someone else cross-posted the exact same question onto the other site, or a very similar question within the past 7 days; these will also result in the migration being blocked if normal users vote.)

See: What is migration and how does it work?

  • 3
    Wow, that's obscure. Thanks for the information that tags can doom a migration. Nov 18, 2018 at 2:49
  • 1
    I will just add that migration also goes through if one of the tags is among the intrinsic tags for the target site. (Although perhaps this falls under the wording that the "tag exists on the destination site", intrinsic tags seem to be less known, so I considered this to be worth mentioning at least in a comment.)
    – Martin
    Nov 18, 2018 at 7:31
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    @Martin I'm aware of that; it just wasn't applicable here. It doesn't fall under that wording. For example, the tag "computers" is blacklisted on Super User, but questions on other sites that don't use an existing tag on Super User but do use the "computers" tag can be migrated without issue. Nov 18, 2018 at 9:01
  • Wow. This seems like a major pain. In this case, there are large classes of questions that are explicitly off-topic for Writing.SE, and on-topic for English.SE; we don't want a tag on our site and we do want those questions migrated...
    – Ziv
    Nov 21, 2018 at 9:21
  • @Ziv Moderators can migrate those questions. If most of these migrations use similar tags, you can request they be added to the "intrinsic" list on English; this way, the community can migrate them without a matching tag. Nov 21, 2018 at 21:18
  • @MonicaCellio See this related feature request I filed partly as a result of your question. Feb 10, 2019 at 1:30

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