Stickies disappeared after upgrading to Sonoma

From Stickies > Help

"Important: If you upgraded to macOS Sonoma from macOS 10.14 or earlier, follow the onscreen instructions when you first open Stickies to import any sticky notes you may have had in the Stickies widget in Dashboard."

I did it! I had the same problem, spoke with many support people @Apple and finally was successful.

I had backed up on Time Machine (months ago). I went to my last backup (prior to Sonoma update).

Clicked on Applications

The old Stickies app was there (the new one too)

Clicked on (old) Stickies

Clicked Restore and voila, all my sticky notes were back! Oddly ones that were newer than the back up showed up too but I'm not complaining.

Now to figure out how I want to handle all that info since Stickies seems vulnerable.

Good luck!

I found this forum post which says that the Mojave Stickies database was located in "~/Library". I have no idea if the old database is still there after your upgrade, but the forum post made it seem like it should be there at least until you upgrade/convert to the new database which will definitely change its location. While this post was for migrating a Sticky Notes database from Mojave to Catalina, perhaps they can be adjusted to work with Sonoma as well.

https://forums.macrumors.com/threads/how-to-migrate-stickies-database-from-mojave-to-catalina.2209792/post-28122114

And also see this subsequent post which mentions what to do if there is no Stickies migration folder on the new OS:

https://forums.macrumors.com/threads/how-to-migrate-stickies-database-from-mojave-to-catalina.2209792/post-28546505

Keep in mind the locations referenced in these two posts are for Catalina. You will need to figure out where the equivalent locations may be for Sonoma.

This post includes some changes related to Big Sur which shows how things changed from Catalina to Big Sur (may be useful when trying to figure things out with Sonoma):

https://forums.macrumors.com/threads/how-to-migrate-stickies-database-from-mojave-to-catalina.2209792/post-30039549

You may want to review the later posts as well.....I stopped reading after these posts. Assuming you still have a copy of the old Mojave Stickies database, maybe these posts can give you some guidance on how to proceed, but keep in mind that Sonoma may have some other differences beyond those made with Catalina & Big Sur. There may be other sites where they may have some information about how Stickies (or whatever they may be called now) work in Sonoma so that you can adjust the instructions from those posts for older versions of macOS. You may be the only person in this situation since most people usually upgrade to the next OS each year instead of skipping multiple OS upgrades so it may be up to you to actually figure things out from small clues & tips like this.

Also, if you have the Mojave Stickies database at "~/Library" (assuming it stayed after the upgrade to Sonoma), then I highly recommend you make at least one copy storing it at another location just to be safe. Personally I would make sure one copy is placed on external media and disconnect the external media before attempting any fixes.

Or do as @dfaye and restore the database from a backup you made before the upgrade to Sonoma. Good job @dfaye!

People should always have frequent and regular backups of their computer and all external media (including the cloud) which contains important & unique data.