How does sync work within Evernote?
All of your notes (unless stored in a local -- that is, not synced -- notebook) are synced to Evernote Web. Evernote's servers house a copy of all synced notes because all of the Evernote client applications, both mobile and desktop, connect to Evernote on the web to get the latest version of the notes for each user.
Evernote's service and software applications are arranged in what's called a "hub-and-spoke" configuration. This means that every single sync operation that takes place will involve Evernote Web (the "hub"). For instance, if you initiate a sync from Evernote on your desktop computer, any new or updated content will be uploaded to Evernote Web so they'll be ready to be downloaded when any of your other devices initiate a subsequent sync.
Occasionally, two copies of the same note will be found to be in conflict. This could arise when a given note is edited in two different locations before a sync has taken place. In this instance, the note may be placed into a temporary 'Conflicting Changes' notebook. In this notebook, you can view both the local version of the note and the conflicting version from the server, then manually apply any changes that couldn't be merged automatically. Once you're satisfied that the original version has all of the changes, delete the version in the 'Conflicting Changes' notebook (as well as the notebook itself, if it's empty).
- conflicting changes