so here is how you fix the sync issue between Salesforce and Outlook
- Go to the Start Menu
- Enter %appdata% in the Search box and hit Enter
- Open folders Roaming | Salesforce.com | Salesforce for Outlook
- Right click on the DB folder and delete
- Delete the DB folder and close the window.
Re open Outlook, then launch your Salesforce for Outlook (double clicking on the icon on Desktop).
Enter your Salesforce username and password.
Click “Allow”. This creates a secure connection between Outlook and Salesforce.
Click Next, and choose the folders you want to sync.
You can use your default folders or click Change Folder
If you want to include private records select the appropriate checkbox(s) and click Save.
Click Next, and then click Done.
Salesforce for Outlook should sync again.
Hope this helps! Feel free to leave feedback below!