Internal hard disk won't wipe, can't reinstall OS because not enough disk space My MacBook Pro 2017 (running Big Sur) is not booting. Instead, it is showing me a flashing folder with a question mark.
When I boot from an external ssd, I can see my data from my internal ssd, but I can't delete something from it.
When I'm in recovery mode, I can't reinstall the os because I don't have enough space, and in disk utility, and when I'm trying to erase my disk, it says: &quot;A writeable disk is required (-69772)&quot;.
What can I do to erase my disk and reinstall the os ?
If you don't want retrieve your personal datas (I suppose they are saved) you can erase the entire disk and after reinstall Mac Os X. I suppose you have an usb key or an apple installer for install your Mac os system.
I refer to this : https://imgur.com/C5yYVeT
The command in the terminal is :
diskutil erasedisk apfs &quot;Alex HD&quot; gpt disk0

This will reinitialise the 128 Go SSD with an APFS Volume named Alex HD