QB Issue Resolution:

First thought: You may be running two copies of QuickBooks Mac.
Second thought: Your file may be busy because some other program is using it or accessing it, perhaps from a different system (if you share your drive with other computers) or from the QuickBooks Mac server (if you use multiuser).

Either way, the best thing to do is to reboot your Mac. That will cause any programs using any files on it to quit or lose connection. Then when your Mac reboots you should be able to open the program.

I don’t think you need to use the backups. If you do the way to do that is to double click on the .dmg files. They will open as virtual read only disks. You then copy the company file out of the virtual disk into your Documents folder (or wherever you want to keep it). Then you’ll be able to open it from QuickBooks.

Resolution for Issue 'How do I correct a message that the company I am trying to open is already running and that it cannot be opened again?' available: Yes (Solved).
Source: Intuit Community forum.

How do I correct a message that the company I am trying to open is already running and that it cannot be opened again?: this 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 issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for Company
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!

Error Recovery for Company [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.

Get 50% off Quickbooks Online

Click Here for 50% off!

Additional Support Options: