Just purchased a used early 2011 MacBook Pro and did a complete new reinstall of Sierra 10.12.6 from Bootstick/Internet including all updates later available for 10.12.6; I was able to download them from the App Store without being signed in.
When trying to sign directly into the App Store I received a failure message:
An unexpected error occurred while signing in. The data couldn’t be read because it isn’t in the correct format.
Additional Information:
- Accessing my App Store account from another MacBook Pro late 2011 with the same OS is no problem.
- Accessing my App Store account from my iPad and iPhone is no problem.
- Accessing my Mac ID, iTunes and iCloud accounts is no problem.
- When signing into iCloud in Preferences the MAC automatically signed me into the App Store (in AppStore\Store\View my Account; it shows the email address currently used). However when trying to download third party apps, the App Store asked me to sign in again and after doing that the same failure message occurs again too.
- No VPN or Virus Software is installed.
- I have only one Internet Network and can not test with another one, however since the problem is only related to this one Mac and the other one runs fine, I assume the Network is not the cause of the problem.
What was done so far, but did not solve the problem:
- Log in / Log out
- Created new App Store password
- Created new Test User.
- Used another App Store account.
- Basic system restart.
- Restart in Safe Mode.
- Apple Hardware Diagnostics via Internet.
- Time reset from Automatic to Manual.
- Resetting the Time Zone.
- Turned off the Firewall.
- Deleted /User/Library/Preferences plists for app store.
- Complete new Reinstall with Time Machine Backup which is working fine on my other MacBook.
- Repeated all the above listed trouble shooting steps, with the Time MAchine Install, problem remains the same.
Just did another complete new reinstall of Sierra 10.12.6 from Boot-stick/Internet, problem remains the same.
Library/App Store/Adoption.plist is actually providing some more information and saying that the Mac s/n is missing. However, the Mac system information is showing the s/n:
Also the Console is showing some log info:
How can I get rid of this problem and sign into my account again with this MAC?