Every new Windows version comes with issues, but the Spring Creators Update is getting users more riled up than usual. In Windows 10 Pro builds, ‘disable web search' Group Policy doesn't work, meaning Cortana will give you Bing results if you like it or not.
It seems that this is a bug, rather an intentional move, but users aren't confident that Microsoft will rush to fix it. The update has already been signed for RTM, and it's an issue that could be advantageous for the company.
After an OS release, the bulk of the focus in on creating the next OS to meet the bi-annual release cycle. We've seen webcam issues take months to fix, only for it to happen again with the next update.
Thankfully, Windows 10 Enterprise and Education don't seem affected by this issue, and some reports suggest it's tied to user profiles in some way. The bad news is that the bug is also present on Redstone 5, Microsoft's next major OS update.
Manual Fix
Though there's still hope Microsoft will fix this in a day one cumulative update, it seems unlikely. If you're an insider already running the build or looking to upgrade on release, there are several methods you can use.
Firstly, Ghacks has kindly provided a registry script that will disable the functionality. However, if you're wary of messing with such tools, some users report that adding bing.com to their hosts file works. Just bear in mind that this will disable all access to Bing, including in the browser, and may have unintended effects.
Of course, users outside of Cortana's 13 regions won't have to worry, as the feature isn't enabled anyway. If it does effect you, be sure to make it known on the Feedback Hub.