Errors are never a joy to deal with, but I’d like to help you out. There are a couple steps to get this one resolved.

First, turn off UAC

Windows 7

  1. Click the Windows Start button and select Control Panel.
  2. Click the View by drop-down arrow and select Large icons.
  3. Click User Accounts.
  4. Click Change User […]

Resolution for 'Classic View issue: 'Can I log into QuickBooks when I continue to receive error message -12,0?' available: Yes.

The Classic View issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the Classic View issue yourself by looking for a resolution described in the article. If it is a complex Classic View issue or you are unable to solve the issue, you may contact us by clicking here or by using other Classic View support options.

For more information about resolving issues related to Classic View in Quickbooks/QBO or to get support for the issue 'Can I log into QuickBooks when I continue to receive error message -12,0?', click the link below: