For many years and through multiple Windows versions, Windows Update logged to c:\windows\windowsupdate.log – simple and functional. But Microsoft’s vision with Windows 10 seems to be fixing things that aren’t broken, and this is no exception.
Opening c:\windows\windowsupdate.log on Win 10 gives you this:
Windows Update logs are now generated using ETW (Event Tracing for Windows).
Please run the Get-WindowsUpdateLog PowerShell command to convert ETW traces into a readable WindowsUpdate.log.
For more information, please visit http://go.microsoft.com/fwlink/?LinkId=518345
Basically, in order to have a human-readable update log, you need to open PowerShell and run Get-WindowsUpdateLog, which as noted above will convert ETW logs to an old-style WindowsUpdate.log which it places on the desktop. It’s an extra step but not too bad. When it works.
Unfortunately, in some (many?) cases you will end up with a log file filled with lines like these:
1601.01.01 01:00:00.0000000 692 5220 Unknown( 31): GUID=c232d8d6-c0ba-3f2d-4ee0-3c6f4b234595 (No Format Information found).
So what’s the problem? Believe it or not, in order for Windows 10 to convert the ETW files to a human-readable log, the system needs Internet access in order to reach Microsoft’s symbol servers. This is yet another functional change that seems to ignore the reality that many larger environments and virtually every school has content filtering in place, which blocks this very access.
In order to fix this, you will need to whitelist all traffic to http://msdl.microsoft.com/download/symbols. If that still does not fix things, you will need to delete the contents of %temp%\WindowsUpdateLog and re-run the PowerShell command.
After doing that, you should once again have a usable log file. Easy, right?