QuickBooks Error 6000-301: a mistake occurred when QuickBooks attempted to access the company file.

When attempting to open the company file, the next error occurs:

Warning: An error occurred when QuickBooks attempted to access the organization file. Please try again.

If the problem persists, contact Intuit Technical Support and offer all of them with the following error codes: (-6000, -301). Click on the Details button to learn more to supply Intuit Technical Support to simply help diagnose the error.
Why this can be happening

This error can be brought on by any of the following:
The company file is damaged.
The Transaction Log (TLG) File is damaged.
Encryption software is installed.

How exactly to fix it
Update towards the latest release.

Go directly to the Update to your Latest Release web page.

IMPORTANT: Make sure your product is selected. Or even, click "Choose a different sort of product."

Select and stick to the instructions for just one of the update options:
Automatic Updates
Manual Updates

In the event that you still have the error message after updating into the latest release, click OK in the error message and then click Send in the next message that comes up.
Solution 1: Fix the error using the QuickBooks Company File Diagnostic Tool
Download and run the QuickBooks Company File Diagnostic Too.

In the event that you still look at error, try the next solution.
Solution 2: If you're running encryption software, disable it.
Contact the software vendor for your encryption software for detailed instructions on disabling the software.
Solution 3: Restore a backup or use Auto Data Recovery to recover your file.

An individual will be able to open your file, make use of the Verify Data utility to test your data.

If this solution does not resolve the matter, you can read discussions and post messages and questions relating to your issue on the Intuit QuickBooks Community site at no cost, you can also contact a tech support team agent for additional guidance.