This problem seems to affect primarily Haswell-based notebooks with Intel HD Graphics drivers in use. I have not yet seen it affect Broadwell chipsets, but it may.
The issue is that the Start Menu text is too dark — and in fact, it becomes gradually darker — and illegible, fading into the background of the Start Menu. While it seems likely that a Windows 10 setting (or theme) should be to blame, it actually is neither.
The problem is the Intel Graphics driver, which includes a setting that purports to implement application-specific fixes. To correct the problem, all you have to do is disable the setting and reboot the PC:
- Right-click the Desktop and choose Graphics Properties…
- Choose 3D.
- Under Application Optimal Mode, click Disable.
- Reboot the PC.
The problem is solved!
It’s likely in the future that Intel will correct their driver optimization presets for the Windows 10 desktop windows manager / Explorer.exe, but until that day, this is the correct workaround.