There are a few ways to remove a registry from a Mac. The easiest way is to use the System Preferences application. To remove the HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Registry key, open System Preferences and select the General tab. In the Registry Editor window, click on the Add/Remove Key button and add HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Registry as the key name. Click on OK to add the registry key. To remove the HKCU.DEFAULT key, open System Preferences and select the Users & Groups tab. In the Registry Editor window, click on the Remove button and add HKCU.DEFAULT as the key name. Click on OK to remove the registry key.