How to recover missing notes since Mavericks update? Very recently I've updated my computer via the Mac App Store to Mavericks. Today when I opened Notes I noticed the background had changed but even more startling was that all my notes were gone! It shows "error 43".

I have an external hard drive and backed up my computer. 

Is there any way to get my notes back?
The notes should be stored in your backup, at least. Check here

Solution is to navigate to ~/Library/Containers/com.apple.Notes/Data/Library/Notes and restore:

NotesV1.storedata
NotesV1.storedata-shm
NotesV1.storedata-wal  

Where ~ is your home directory e.g. /Users/your_username

Refer macrumors
or apple discussions
for more info.