How can I fix time that didn't sync to QuickBooks Online or TSheets?

You can use the Batch Update Time screen to filter for time entries that failed to sync and then take actions to fix them.

1. Go to the Manage > Batch Update Times screen. 
2. Choose a time period and check the Failed Sync box.
    
3. On the next screen look at the time entries to see what might have caused the failure to sync. Common issues include missing Time Entities, missing Service Items or Classes (especially if you are syncing to TSheets), missing Customer on times marked as Billable. Note that each time entry on this screen has two rows of information: 
   
    
4. To make changes, select the times you need to make changes to, select the information in the center section of the Batch Update Times screen, and then click the Change Selected Times button. 
   
5. Alternatively, you can edit the time entries one at a time by clicking on the date. 
   
6. If you can't figure out what is wrong, try selecting all by checking the box to the left of the Date column header and the syncing the selected times. Then navigate to Admin > Manage Integrations to look at the sync log for errors.