You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

monterey 12.1 installation failing from 12.01 (tried PRAM reset, safe boot, full installer - no luck so far)

I have monterey 12.01 installed on MacBook Pro (16-inch, 2019) 2.4 GHz 8-Core Intel Core i9 2TB disk with 1.73 TB available.


I am not able to successfully update to 12.1 using the Software Update functionality (even after PRAM reset and Safe Boot mode), or using the installer downloaded via:

softwareupdate --fetch-full-installer --full-installer-version 12.1

(even after PRAM reset and Safe Boot mode)


Below is a screenshot of the issue I get via the full installer.


When using the Software Update functionality, the download portion seems to complete, but either it gets stalled at "Preparing for macOS Monterey 12.1...." stage with about 5 minutes estimated remaining (below image is similar to this but at an earlier stage), or occasionally it seems to error out at this stage with an error message relating to a time-out issue or a download issue.


MacBook Pro with Touch Bar

Posted on Dec 15, 2021 12:17 PM

Reply
Question marked as Top-ranking reply

Posted on Dec 15, 2021 12:37 PM

Next delete the existing installer which is located in the Applications folder. Then boot to Safe Mode. That boot up takes minutes and clears caches and other things that may resolve your problem.

How to use safe mode on your Mac - Apple Support

Similar questions

14 replies

Dec 15, 2021 2:32 PM in response to lllaass

Thanks Illaass! As I mentioned in the subject of this issue, and in my description, I did already try safe boot mode. I did delete the installer I had downloaded via

softwareupdate --fetch-full-installer --full-installer-version 12.1

then booted into safe boot mode, and then tried to update via the Software Update method.


It is so strange - the install process seems to be going perfectly and concluding, but once it boots up, I'm still in 12.0.1.


Any ideas?

Dec 15, 2021 3:42 PM in response to NathanHillson

I chatted with Apple Support, and they said the next step in the escalation process would be to do a clean reinstall of the operating system, which would have the downside of wiping out all my files. Not a show stopper, since I could back up and then restore - but I'd greatly prefer to find another solution.


I am trying to download 12.1 from the app store (rather than the Software Update route) - but not sure that will be any different than the

softwareupdate --fetch-full-installer --full-installer-version 12.1

approach I have already tried.


Any suggestions most welcome - seems so strange the the upgrade to 12.1 seems to be working so well, only to result in being back in 12.0.1.

Dec 16, 2021 10:59 AM in response to NathanHillson

Here is the latest thing I tried, with the error log message. Hope this can help someone diagnose, or others having similar issues:


njhillson@njhillson-mt ~ % sudo softwareupdate -i -a -R

Password:

Software Update Tool


Finding available software

Downloading macOS Monterey 12.1

Downloading: 100.00%

Failed

to download & prepare update: Error Domain=SUOSUErrorDomain

Code=201 "Failed to prepare the software update. Please try again."

UserInfo={NSLocalizedRecoverySuggestion=An error occurred

while downloading the selected updates. Please check your internet

connection and try again., NSLocalizedDescription=Failed to prepare the

software update. Please try again., NSUnderlyingError=0x60000175c240 {Error Domain=SUMacControllerError Code=7740 "[SUMacControllerErrorPrepareFailed=7740] Failed to perform Prepare operation: [MobileSoftwareUpdateErrorDomain(MSU):MSU_ERR_BRIDGEOS_PREPARE_FAILURE(45)_1_BOSErrorDomain:204_2_BridgeOSSoftwareUpdateError:19]" UserInfo={NSLocalizedDescription=Failed to prepare the software update. Please try again., SUMacControllerErrorIndicationsMask=0, NSDebugDescription=[SUMacControllerErrorPrepareFailed=7740] Failed to perform Prepare operation: [MobileSoftwareUpdateErrorDomain(MSU):MSU_ERR_BRIDGEOS_PREPARE_FAILURE(45)_1_BOSErrorDomain:204_2_BridgeOSSoftwareUpdateError:19], NSUnderlyingError=0x600001768300 {Error Domain=MobileSoftwareUpdateErrorDomain Code=45 "bridgeOS prepare failed" UserInfo={NSUnderlyingError=0x600001768480

{Error Domain=BOSErrorDomain Code=204 "An error occurred during

preflight." UserInfo=0x600000c6c200 (not displayed)},

NSLocalizedDescription=bridgeOS prepare failed, target_update=21C52}}}}}


monterey 12.1 installation failing from 12.01 (tried PRAM reset, safe boot, full installer - no luck so far)

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.