I have been running Windows 10 via Boot Camp for several years. I finally decided to upgrade the OS X side from El Capitan to Catalina. I had no issues after the update except the default boot disk reverted back to OSX. I was able to boot into Windows by holding alt/option. A few days later, I was having a wifi issue in Windows and so I booted into the OSX side to download the latest Windows Support Software. During the software download I received an error stating that the Windows Support Software could not be saved to the specified location (I had forgot to insert a valid USB drive). I had to hard shut down the computer. Since then, my Windows partition is no longer visible in Finder or Disk Utility, nor is it showing up as a boot disk in system preferences. It appears that section of the Hard Drive is showing up as free space. I am looking for some direction on how to troubleshoot and begin to restore my Boot Camp partition. Any help is appreciated.