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Big Sur Installation Un-completed

After downloading Big Sur into my 2017 MacBook Pro 13" , the following shows up: "An error occurred while preparing the installation. Try running this application again". Is there's any help to handle this?

Thanks!


[Email Edited by Moderator]

Posted on Dec 12, 2020 4:34 AM

Reply
Question marked as Top-ranking reply

Posted on Dec 16, 2020 7:33 AM

francopellicier wrote:

After downloading Big Sur into my 2017 MacBook Pro 13" , the following shows up: "An error occurred while preparing the installation. Try running this application again". Is there's any help to handle this?
Thanks!

[Email Edited by Moderator]


Yes, run it again.


Big Sur states that you will need 35.5 GB of free storage when upgrading from High Sierra or newer, and 44.5 GB when upgrading from an older versions.


If you still have the full installer it is sitting in your Application folder— "Install macOS Big Sur.app"


If you have the free storage available you can reboot into SafeBoot mode if your issue continues—launch the installer from this environment.


SafeBoot https://support.apple.com/en-us/HT201262

Takes noticeable longer to get to the login screen, does a 5-15 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc. Login and test. Reboot as normal and test as caches get rebuilt.


In Safe mode third party system modifications and system accelerations are disabled, it removes malware, etc hampering smooth operation, however a reboot will put it back to normal mode.


third party interference; extensions etc are not loaded in safe boot mode.


3 replies
Question marked as Top-ranking reply

Dec 16, 2020 7:33 AM in response to francopellicier

francopellicier wrote:

After downloading Big Sur into my 2017 MacBook Pro 13" , the following shows up: "An error occurred while preparing the installation. Try running this application again". Is there's any help to handle this?
Thanks!

[Email Edited by Moderator]


Yes, run it again.


Big Sur states that you will need 35.5 GB of free storage when upgrading from High Sierra or newer, and 44.5 GB when upgrading from an older versions.


If you still have the full installer it is sitting in your Application folder— "Install macOS Big Sur.app"


If you have the free storage available you can reboot into SafeBoot mode if your issue continues—launch the installer from this environment.


SafeBoot https://support.apple.com/en-us/HT201262

Takes noticeable longer to get to the login screen, does a 5-15 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc. Login and test. Reboot as normal and test as caches get rebuilt.


In Safe mode third party system modifications and system accelerations are disabled, it removes malware, etc hampering smooth operation, however a reboot will put it back to normal mode.


third party interference; extensions etc are not loaded in safe boot mode.


Dec 16, 2020 7:24 AM in response to francopellicier

Hello francopellicier,


Welcome to Apple Support Communities!


We understand that after downloading Big Sur you're getting an installation error. We're happy to help!


What happens if you restart your Mac? Does it keep looping back to that same error message?

Log out, sleep, wake, restart, or shut down your Mac


You can also reinstall the macOS if it keeps looping back to the same error message.

How to reinstall macOS


Let us know if you have any questions.

Thank you for using Apple Support Communities.

Take care!


Big Sur Installation Un-completed

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