Oeps it happened again, Windows doesn’t recognize my Android phone and doesn’t show it in the Explorer. This has happend a few times with different Windows 10 builds, I have no idea why exactly. The fix is easy to apply.
When opening the Device Manager (devmgmt.msc) you see a yellow warning sign with an error.
You can probably fix this very easy by re-installing the MTP driver. All you have to do is going to the C:\Windows\INF location on your computer and look for the file wpdmtp.inf.
Right-click on wpdmtp.inf and choose Install
After this your phone will be recognized and visible in the explorer.