VelcroJP wrote:
Hi Ikrupp, you seem to know something about this issue? I recently ugraded to 26.1 (and now think I was stupid to do so!)
SOME of my e-mail passwords seem to have arbitrarily changed! I tried to log in direct to the mail server but the "keychain" passwords did not automatically appear. I opened "Passwords" and copied the password and pasted it into the field on the log-in -- it was deemed incorrect. I went through the "Forgot password" process and updated the password. To ensure my other devices (iPhone running iOS 26.1 and iPad running iOS 18.72) would also log-in, I opened "Passwords" (on the Mac) and edited the password -- which had not been automatically updated -- and completed what I had been doing.
I restarted my Mac this morning and password was again deemed incorrect, so I changed it again.
I then TRIED to log in to my favourite radio station -- which I can access only through the Internet -- and, again, the keychain password was deemed incorrect. I opened "Passwords" and copied the (plaintext) password, pasted it into the log-in and that was deemed incorrect.
Is it possible to revert to the previous version of Mac OS? (I was already using iOS 26.1 on my iPhone -- for about 10 days -- with no apparent problems.)
H E L P , please.
I will only speak to the Apple Computers issue in regarding Downgrading to a Previous version
As for iOS devices and downgrading
Once the newer version of iOS is released. Normally, Apple will Cease Signing Older Versions of iOS making it impossible to downgrade
macOS ?
User Risk Assessment: macOS Downgrade Procedure
Before initiating any downgrade from macOS 26 (Tahoe) to an earlier version such as macOS Sequoia, assess the user’s tolerance for potential risks. The following checklist must be completed before proceeding.
Primary System Dependency
Determine whether the affected Mac is the user’s primary or only computer.
If the user cannot function without this system for several days in the event of a failed downgrade, the risk level is high.
The downgrade should be postponed or avoided until proper contingency measures are established.
Availability of a Secondary macOS System
Confirm that the user has access to another Apple computer currently running macOS 15 or macOS 26 (Tahoe).
This secondary system must be capable of performing a Revive or Restore operation on the target Mac’s firmware if required.
Lack of a secondary Mac significantly reduces the ability to recover from firmware corruption or boot failures.
Firmware Compatibility and Secure Enclave Risks
Be aware that upgrading to macOS 26 (Tahoe) likely includes a firmware update affecting the logic board and Secure Enclave Processor (SEP).
Downgrading to an earlier version (e.g., Sequoia) may introduce firmware mismatch issues, leading to instability or loss of functionality.
There have been at least three documented cases where downgrading from Tahoe to Sequoia resulted in Secure Enclave malfunctions, requiring full system restoration or hardware servicing.
Backup Integrity and Recovery Preparedness
Verify that the user has at least three complete backups created before the macOS 26 (Tahoe) upgrade.
Implement the 3-2-1 Backup Strategy:
3 total copies of essential data
2 different backup methods or storage media
1 copy stored offsite (for protection against natural or human-caused disasters)
Each backup should reside on a dedicated, single-purpose external drive.
For enhanced backup and cloning capabilities beyond Time Machine, refer to:
🔗 https://bombich.com
Recommendation Summary
If the user answers NO to any of the above questions:
Downgrading the Mac is not recommended.
Proceeding without proper contingency plans, verified backups, and recovery tools may result in:
Data loss
Firmware corruption
Secure Enclave failure
Complete system inoperability
_______________________________
