Booting from internal or external volume not possible
Trying to boot from internal volume results in dispaying a folder symbol with question mark. When trying to boot from external volume by pressing OPTION key there are no booting options available. Only a key symbol with password entry is displayed but I did not configure any BIOS keyword or volume encryption. Tried to reset SMC and NVRAM but did not help. Do you have any idea to fix it?
Ist dies eine gute Frage?
What kind of file-format does the external device have? Is it possibly write-protected?