How to fix Bootcamp Windows Partition not showing in iMac running High Sierra

diamonrun wrote:

Hi, thank you for replying. I was wrong: I meant option key.

I solved my problem another way: I deleted the partition I had created. I downloaded the Windows 8.1 iso file and burned it to a DVD. I used bootcamp to install Windows 8.1: bootcamp downloaded Windows support with all the drivers for Windows and I saved everything on a USB stick. Then bootcamp created the partition to install windows and then the installation started. The installation was successful. I installed the drivers by starting setup on the USB stick. Then I did all the Windows updates and installed the Apple updates. When I finished updating the system with all available updates, I verified that I could switch from Windows to Apple and vice versa. It worked. Then I decided to download the Windows 10 ISO and upgrade Windows 8.1 to Windows 10. I started the setup inside Windows 10 and the upgrade began. Now I have Windows 10 working and I can switch from Windows to Apple and vice versa without problems.

I can consider myself satisfied and I believe that this question can be considered concluded.

Thanks to everyone and see you soon.

Perfect, glad you figured it out.

diamonrun wrote:

Hi everyone. I apologize in advance for my bad English but I am Italian. I hope you can help me because I have consulted all the discussions and I can't find a solution to my problem. I have an iMac mid 2011 macOS High Sierra 10.13.6

I created a 163.97 GB partition on which I installed Windows 10 pro. The installation was successful. I have updated Apple Software Update and installed all the latest updates. I restarted my PC via bootcamp switching to macOS. In macOS I restarted the PC and pressed the command key but the bootcamp partition with Windows is not present. In macOS the bootcamp volume is present and visible. In Startup Disk the bootcamp volume is present and selectable. When I select bootcamp and restart the PC there is a black screen that remains forever.

How can I make the bootcamp volume appear with Windows when I press the command key?

Your English is excellent. Is it the Command (⌘) key you're pressing and holding or the Option (⌥) key? The Option key is used to enter the disk selection screen, so I'd try that if you aren't already.

As for the black screen, that can sometimes be a brightness issue- I'd try resetting the PRAM/NVRAM. Shut down the computer, then hold these four keys together while starting the computer: