Tive o mesmo problema e precisei reinstalar a cópia local das minhas anotações, uma sugestão que recebi em outro grupo. Na época resolveu, mas já está voltando a travar um pouco novamente. Acredito que de tempos em tempo será necessário repetir os passos (está em inglês). Espero que ajude!
To rebuild your Evernote for Windows database, follow these steps:
If you don't have any unsynchronized notes, and you do not have Local notebooks, please skip to "Move your existing Evernote database." If you do have unsynchronized notes or local notebooks, follow these steps to export that content:
Select all unsynced notes, or each local notebook, then right-click and select Export Notes…
Choose 'Export as a file in ENEX format (.enex)', then click Export
Detailed instructions here
Move your existing Evernote database:
Select: File>Sign Out
Reopen Evernote
Select Evernote > Options
Select Sync>Enable On Demand Sync
Select General> Open Database Folder
Right-Click the username.exb file in the database folder window and select Cut
Right-Click the Windows Desktop, and select paste so that the username.exb file is no longer in the database folder and now on the Desktop
Close the Database Folder and Options Windows and log back into your account.
This will remove the existing database of notes saved to your PC. When you log back in, the "On Demand Sync" option will decrease the initial sync time, by not attempting to download the entire database at once. As you open the notes you need they'll be downloaded in smaller batches.