The "Initialization Failed" error is usually caused by a corrupt database. In most cases, this can be resolved by removing and re-adding the affected account to the Insync app:
Remove your account from Insync
Add it again to the app (this will take you to initial setup).
During setup, you may select your existing Insync folder (make sure to select the correct folder) so there would be no need to upload or download.
SCANNING FOR CHANGES
If your Insync app is stuck at "Scanning for changes", please try to re-install the app and log in to your Google Account again.
Files have stopped syncing (files are stuck on queue, no progress is happening) or Insync is syncing everything from Google Drive automatically upon initial setup (no option to Selectively sync files)
This problem has been found to occur across newly set-up accounts on Insync. The recommended fix for this is to re-setup your account:
Install the latest Insync (if it hasn’t auto-updated for you already)
Add account again and select an empty folder as Insync folder during setup
CONNECTING TO INSYNC
Once you have authenticated your Google Account, your browser will say "Connecting to Insync...". In case it gets stuck, try these steps:
TEAM DRIVE FOLDER
I don’t need/want to sync Team Drives on my computer! Can I delete the default sync folder for Team Drives?
As long as you haven’t synced any of your Team Drives, it should be safe for you to simply delete the folder from your computer.