You are probably facing QuickBooks Error 6000 77 if you access your company file following the mapped drive path. Instead switch to the UNC path like this -
Go to the QuickBooks icon on your desktop screen and right-click over it.
Hold the Ctrl key on your keyboard and select the “Run as Administrator” option.
When the app opens, tap on the File tab and choose “Open or Restore Company.”
Then press “Open a company file” and hit the Next button.
Click on the Network option and search for your company file.
Choose your file and hit Open.
The above solution should resolve Error 6000 77 QuickBooks for you. If not, you can opt for on-call support offered by the pro-advisors at 1-855-856-0042.