Lost Notes After Update to Big Sur

[wolf7988]

Hello everyone, I am in dire need of help. More specifically, I recently updated my MBP from Yosemite to Big Sur, and for whatever reason, it deleted all of my saved notes from the Notes app. I did find a folder that said "Notes backup", and I believe this may be the backup copy that maybe they automatically save prior to the update. However I can only open it in TextEdit and it's all weird characters and unreadable. It is an SQlite file and the new Notes version can't read the previous SQlite file I guess. I downloaded an sqlite file reader but it asks for an encryption key to unlock, which I don't recall creating and don't know the key (unless mac automatically creates this key and saves it for me somewhere that I can access...?).

Wondering if any one has seen this issue before or if anyone might know of a solution. I didn't back up to icloud and no Time Machine because it is very private/important info (I thought I had the specific note I needed printed out in a safe with my other important notes but apparently I didn't... stupid, I know). It is a very valuable note that I must recover. I am willing to pay anyone who can get this back for me. I tried sending the back up file to a different Mac that's on High Sierra, however it didn't seem to work (or maybe I don't know what I am doing). I have the backup file saved and copied in case I messed anything up.

Thanks in advance for any help!

 

[Honza1]

Do not have experience, but my expectation would be that the key ("password") for those old notes is in Keychain. It was automatically generated to protect your privacy and is shared (using iCloud) between macos and ios for that specific user to enable opening Notes on both platforms. Make sure you have backup of the keychain from High Sierra. If you are lucky, the key for notes might be identifiable by name, you can try to browse that keychain using keychain access.app.
I would assume that Notes on the other HS machine needs your keychain to open these old notes. Does it have the same keychain?