My hard drive is erased and the OSX Base System is ok. What do I do next to use my computer?

Depending on the age of your computer you can either boot into:

• Recovery Mode (Command + R)
• Internet Recovery Mode (Command + Option + R)
• Boot a macOS USB installer
• Boot an OSX DVD installer (preferably OSX 10.6 Snow Leopard)

Once you successfully boot using one of these methods, you just click "Reinstall macOS".

Which method did you choose for booting?

At what point did you receive this error message?

What version of macOS installer is it?

What is the exact model of your computer? You can get this information by entering your serial number here or here.