Software installation problem

[Waldo3333]

I received a notification of a system upgrade to Sierra, I think it was so I accepted and began the installation. After a while the message "Installation failed on this computer" or words to that effect, appeared and I was asked to restart it. This I did but now all I am getting is a blank screen with a flashing white box containing a large black question mark!
Do you have any idea what has caused this and what I can do about it, please?

 

[honestone]

Need some more information:

1. What exact Mac model do you have?

2. What exact Mac OS were you using before you tried to upgrade to Sierra?

3. This is critical: are you making backups to an external device? And if you (hopefully) are, what software are you using for that?

4. Have you ever done any disk cleanup/maintenance/repairs from a software perspective? You can actually do quite a lot of disk cleanup on your own, and there are some excellent products available (both free and commercial) that can help you with those tasks. Two of the best (that I use) are Onyx and Tech Tool Pro.

5. What third party apps (ie, non-Apple) do you use?

6. How are you making posts here? If it is via another Mac, what exact model is it?

Once you answer those questions, we can help you.

 

[Waldo3333]

Need some more information:

1. What exact Mac model do you have?

2. What exact Mac OS were you using before you tried to upgrade to Sierra?

3. This is critical: are you making backups to an external device? And if you (hopefully) are, what software are you using for that?

4. Have you ever done any disk cleanup/maintenance/repairs from a software perspective? You can actually do quite a lot of disk cleanup on your own, and there are some excellent products available (both free and commercial) that can help you with those tasks. Two of the best (that I use) are Onyx and Tech Tool Pro.

5. What third party apps (ie, non-Apple) do you use?

6. How are you making posts here? If it is via another Mac, what exact model is it?

Once you answer those questions, we can help you.

Thank you very much indeed for your reply. Happily, I have been able to resolve my problem and all is OK again!
Best wishes

 

[honestone]

What was the resolution?

Also, what about backups, and disk cleaning/maintenance/repairs? Hopefully you are being diligent and performing those tasks.