I got a HP 6300 with a i5-3570K, installed Catalina successfully. Since my monitor is old, after I changed the resolution and the screen blank. I perform the recovery thru Clover but got a error message at about 75% then I boot in Win10 and delete the Catalina and the EFI partition (a whole separate drive with WIN 10) and clean install again. But when I choose install Catalina in the Clover menu (no recovery icon there), it boot in recovery mode, in Disk Utility, a osx system base disk image there and cannot be deleted. I tried to install in the formatted drive (HPS format) but not allowed since it does not have GUID map table(no this option choose in Disk Utility, just have Name and format type), therefore no drive is allowed to perform a clean install. I would like to ask what can I do? Where is the osx system base and how can I delete it? Thanks a lot.