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Big Sur RC2 Full Install & Upgrade on a T2 Mac = “An error occurred installing macOS”

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UPDATE 11/12/20!! For the new installer issues I’ve created a new video!

THIS IS THE PREVIOUS RC2 Install problems Video! When you attempt to install or upgrade on a T2 Mac, you will get the error – “An error occurred installing macOS. You can try again to complete the installation”. in the install.log you will see “The bridgeOS update doesn’t satisfy the given minimum version requirement.”
Almost immediately after macOS Big Sur 11.0.1 (20B28) was released, I started to see reports of install issues. This was only happening on T2 Macs that need a BridgeOS update. A BridgeOS update is included and required with almost every combo, delta and full installer upgrade or install. Below is the 11.0.1 RC2 Install error.

The problem is the new production Software Update Catalog URL does not have the needed BridgeOS update yet.

The problem comes down to the installer looking to the new production SUS url. Apple just made the production SUS catalog available. The new URL is

New Big Sur Production SUS URL =

https://swscan.apple.com/content/catalogs/others/index-11-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog

Big Sur Beta SUS URL =

https://swscan.apple.com/content/catalogs/others/index-10.16seed-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog

The production URL does NOT include the required BridgeOS update needed for the Big Sur RC2 installer to continue.

Notice this line

“The bridgeOS update doesn’t satisfy the given minimum version requirement.” UserInfo={bridgeVersion=17.16.16610.0.0,0, minimumVersion=18.16.12561.0.0,0, catalogURL=https://swscan.apple.com/content/catalogs/others/index-11-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog

I track all T2 BridgeOS updates here

mrmacintosh.com/macos-system-status-version-info-for-macadmins

This is what the new Big Sur 11 production SUS looks like right now.

Set the SUS server to the DeveloperSeed SUS URL.

To resolve this issue we can use the nvram binary to set the SUS catalog to the correct one that has the BridgeOS update that we need.

sudo nvram IASUCatalogURL=https://swscan.apple.com/content/catalogs/others/index-10.16seed-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog

You can use sudo nvram -p to view all the nvram settings.

NOTE! When you are done with the upgrade, don’t forget to remove the value!

sudo nvram -d IASUCatalogURL

Links
https://MrMacintosh.com – Apple Mac Enterprise IT Blog & macOS News for MacAdmins

Twitter
https://twitter.com/ClassicII_MrMac

Mac Transition to Apple Silicon Everything you need to know!
https://mrmacintosh.com/mac-transition-to-apple-silicon-everything-you-need-to-know-updated/

MacOS Big Sur Index of need to know changes! (UPDATED)
https://mrmacintosh.com/macos-big-sur-11-index-of-need-to-know-changes-links-updated/

macOS System Status (Issues) – OS, Xprotect & App Version Database
https://mrmacintosh.com/macos-system-status-version-info-for-macadmins/

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16 Comments

  3. So…3 month from release…I still have the same issue with the same logs on Mohave. What do I need to do to refresh my bridgeOS???

  5. I got the same error when I upgraded macOS Big Sur 11.0.1 production version. I tried to use your solution but doesn't work. My model is MacBook Pro 16". My present version is 10.15.7.

  6. I got the same error last night. Today I have installed it with no issues. I have a question If you can help. My brother wants to upgrade his Mac mini today with Catalina (from Mojave) and not Big Sure, his Music plug ins may have issues. How is it possible? Thank you in advance and greetings from locked down Greece

  8. I loved the tutorial, but I'm still scared to do it on my Mac (2020 mbp) so do you think that apple is going to fix this issue officially??? I'm so disappointed, I waited so long for the release and now I can't install it….

  10. Hi, I’m still having abit of trouble figuring everyone out, if you can make a step by step guide for people who doesn’t know how to use coding or terminal, it would really be awesome

  12. it didn’t worked now i have this notification ”An error occurred while installing the selected updates.”
    I have no idea what I did wrong

    Edit: I shut down my mac and now I have this notification ”Unable to check for updates make sure you are connected to the Internet ”
    And I am connected .

  15. I wont execute that code even if I would be crazy, how do I don't know that I am allowing a back door to my mac. I will wait for the official Apple forums to see a fix.