有小部分人遇到这个问题了，一直无法升级，下面是微软的说法：


微软社区有工作人员回复这个问题了，妈的，说从WP8.1升级上去10572的机子会有一部分会遇到这个问题，解决方法是滚回WP 8.1，然后再升级10581。并说10581以后就不会再有这个问题，鬼才信呢。

It looks like you folks are hitting a known issue which can impact some phones that started from an 8.0 build and updated all the way to 10572. We've fixed this bug since then, so it shouldn't impact 10581 and higher. However, to get yourself good again you'll need to recover your device using the Windows Device Recovery Tool and go forward again. Followthese steps to backup your stuff and recover.






上次升级10572的时候，让我们滚回WP8.1，现在又要滚回去。上面还有网友说没看到10581的更新日志有提到已经修复这个问题。那个微软工作人员又说：


It can be the case that we don't always capture all known problems in the blog, but we do an earnest attempt at capturing the largest of them. Still, this one may have slipped through our fingers and didn't get a chance to mention it.

We know the issue and the unique circumstances at which it can occur, so not everyone will hit it, but if you do fall into this state unfortunately the work around steps I mention are needed. Note, it is definitely our goal to ensure going back to 8.1 and forward is an infrequent (as possible) occurrence. On a positive note, doing this step actually helps us get data which will aid when we have public users going from 8.1 to 10. So, in a way, you are very much helping us blaze a clear path ahead.



上面大概意思是说已经修复了，但忘记写进更新日志里面去了。