A week ago my Evernote app suddenly stopped working with the 'an internal database error has occurred' error which prevented Evernote from opening. All but one of my Notebooks is synchronized online but I had a critical local-only notebook (for security reasons) which I could not afford to lose. After spending some time browsing how Evernote stores data in 'Application Support', I discovered that my note content was still there.
I spent the rest of the day writing a program which can directly extract all of the enml files under 'Application Support' and export them into a single export file in enex format - independent of the Evernote app and regardless of whether the database is corrupted or not.
I called the program "Evernote Doctor" and it's free for anyone to use.
NOTE: It is provided "as is" w/o warranty, liability, claim, contract, tort, or otherwise in connection to the use of the software (see software LICENSE).
It has the following limitations:
It does not recover note titles. This can be significant, I know, but for my purposes simply having the note content was infinitely better than not having that at all and I was able to reconstruct my note titles from re-reading my notes.
It exports all notes across all notebooks (online and local-only - any enml file on disk under Evernote's 'Application Support' location) so once one repairs the Evernote app so the export file can be imported, they will need to search through that potentially large import notebook in order to find the notes from the local-only notebook.
If someone knows how to overcome these limitations, I'm happy to see about working that into the program. I assume that it's unlikely since #1 and #2 are part of the database which is corrupted.