Naturally, being one of the most used features, having the search bar not working can be really frustrating. Some users suspect that the bug was caused by Bing integration. In fact, a Reddit user managed to solve the problem by disabling Bing in the Windows 10 Start Menu. Someone else on Twitter managed to get it fixed by restarting Windows Explorer via the Task Manager.
— Sunil (@su2nil) February 5, 2020 While there are workarounds for this issue, you may not actually have to do anything yourself. According to the BBC, Microsoft has since announced that it has resolved the issue for most users. If you’re affected by this and are still seeing a big blank box rather than your search results, then you’ll likely need to restart your PC first. While it’s an annoying bug for sure, it looks like it’s been resolved quickly enough that you won’t have to deal with it for too long. Having it now being resolvable with just a simple restart is also a bonus, as it requires way fewer steps than, say, actually disabling Bing. (Source: BBC, Reddit)