Error:
QuickBooks already has a company file open. If you want to open another company file, close this one first. Only QuickBooks Accountant and QuickBooks Enterprise Solutions can open two company files at once.
Solution:
This occurs if either QuickBooks or Atlas is set to 'Run As Administrator' while the other program is not. You can easily check/change this setting by right-clicking on either applications icon on the desktop and selecting 'Properties'. On the 'Compatibility' tab you can check the box for 'Run this Program as an Administrator'.
