QB Issue Resolution:
I suggest to reboot the computer on which you are working. Turn the computer on and open QuickBooks. If you still cannot open the company file, download and run the QuickBooks File Doctor.
Resolution for Issue 'Problems opening a QBW file.Error code is -6000, -301.File is used regularly but failed to open last week. Used on a standalone system, home network.' available: Yes (Solved).
Source: Intuit Community forum.
Problems opening a QBW file.Error code is -6000, -301.File is used regularly but failed to open last week. Used on a standalone system, home network.: 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 error code
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!
Error Recovery for error code [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.
Additional Support Options: