Boot Camp Partition Unavailable After Windows 10 Upgrade I have a simple problem for you today. I have been using Boot Camp with my Mac Mini for about two years and now, after upgrade from Windows 8.1 to Windows 10, the Boot Camp partition doesn't seem to appear in the Finder anymore.

I can still boot Windows up by holding the alt/option key at the startup but OS X acts as if the partition didn't exist.

Here are the symptoms:


The partition has disappeared from the Finder.
Boot Camp tray icon has the 'Restart into Windows' option grayed out.

Disk Utility shows the partition under name disk0s4. Moreover, when I hit 'Mount', it immediately gets unmounted again.




What do you think could cause this situtation?

Thanks in advance,
Pete.
Reason for that is that windows doesn't fully shut down and goes into hibernating mode where the partition is read only... 
Go into the system setting of windows and uncheck the "fast restart" in the energy settings. Then fully shut down and it shows up.