How can I identify a sync error that's only reference to an accouint id id=177845145266552065?

Hello Walterb123,

Sorry, to hear that you're experiencing this trouble.

I would start by resetting the cloud data.

    1.  Edit > Preferences > Quicken ID Sync & Alerts

    2.  Click the link to “Reset your cloud data”

If the issue persists, I would take a look at the steps outlined here.

Let us know how it goes!