Can not upgrade to El-Capitan because the main boot disk is grayed out

[sdancer75]

Trying to upgrade Snow Leopard (10.6.8) to El Capitan, I can not select the primary boot disk called "Snow Leopard" because it is grayed out.
When I click on it, I get the following popup message (free translation from Greeks) "The selected disk can not be used as a boot disk". I can confirm that disk utilities reported no error and the partition map scheme is GUID. What seems to be the problem here? Any solutions?

Best Regards,


PS : I don't want to make a clean install.

 

[fivos1996]

Sorry for the late reply. What is the SMBIOS set to (i.e. model identifier)?

 

[sdancer75]

Hi,

Thank you for your time..... (are you Greek? I just looked up your nickname fivos.... )

Anyway, I managed to bypass this problem by creating an installation USB. Now I upgraded to High Sierra but I am unable to boot from the hard disk except the USB only.

The error I get is a no-sign image and immediately the system is going to sleep mode, but the verbose mode reported that the system is not supported. Now I suspect (I am not a macOS user and I don't have the experience needed) I get to change someway the SMBIOS from the boot manager (clover). I was a little busy lately so I did not find time to rout about this. I will check this out tomorrow.

 

[Nodarkthings]

It's a good idea to check if your current SMBIOS is compatible BEFORE updating...
Now that you've updated, you have to meet the 10.13 requirements: https://en.wikipedia.org/wiki/MacOS_High_Sierra#System_requirements