Keychain Backup Not Loading

[Kurtisx]

Macbook Pro mid-2012

I'm using a Western Digital Elements 2TB external hard drive as my main drive for the time being. So far so good, surprisingly speedy for a hard drive.
The only hitch is I haven't been able to get my Time Machine keychain backup added. I go to the library of my backup hard drive, grab the login.keychain-db file and put it on my laptop desktop. I change the keychain name, then click File -> Add Keychain -> Add. None of the dozens of passwords I have on that backup show up. And yes, the password is the same on both the backup and my current.

What am I missing? I've even tried to migrate the keychain but when I enter Time Machine it doesn't allow me to go to the previous backups I have on there.

 

[NoBoMac]

Might be out of luck.

Note: You can’t copy passwords stored in your Local Items or iCloud Keychain.

Copy keychains to another Mac

Use Keychain Access on your Mac to transfer your keychains to another Mac.

support.apple.com

 

[Kurtisx]

Might be out of luck.

Copy keychains to another Mac

Use Keychain Access on your Mac to transfer your keychains to another Mac.

support.apple.com

That's for Sonoma. I use Catalina, which does allow manual transfers. As I have done various times before.

I guess the hitch might be that I'm using an external hard drive rather than an internal one? I've been trying to install a Kingston SSD inside the laptop, but the installation hasn't gone through even with APFS as the format.

 

[NoBoMac]

Oops! My bad. Did not catch which version.

But even so, using iCloud Keychain? Believe those are no go even with Catalina.