A bug was serious enough to delay Redstone 4's rollout for 'a couple of weeks'. Microsoft's Windows 10 Spring Creators Update was due to arrive on Tuesday but as a serious bug was discovered at the last minute the launch has been put back by a couple of weeks, according to Windows Central editor Zac Bowden. A so called 'blocking bug' in Windows 10 version 1803 was discovered ahead of its scheduled widespread rollout thanks to feedback from Insiders in the Fast, Slow, and Release Preview rings - saving Microsoft issues and tissues.