The "Could not start QuickBooks" error may occur when using QuickBooks Online via Skyvia Agent if QuickBooks and the Skyvia Agent are running with different user permission levels.
Ensure that both QuickBooks and Skyvia Agent are launched with the same permission level, either both as a regular user or both as an administrator. Mixing permission levels (e.g., QuickBooks as administrator and Agent as regular user, or vice versa) can cause this error.
If this does not resolve the issue, refer to the Intuit troubleshooting guide: Troubleshooting: Could not start QuickBooks.