Thanks for getting back to us, @btks.

As per my colleague discussed above, sign in with your Intuit account is mandated only with the following scenarios:

• A new QuickBooks Company file is created.
• If you have the following connected services: Payments, Payroll direct deposit, TSheets time tracking, Payroll Workforce, Receipt Management (new for QuickBooks 2021), and more to come.
• When an existing QuickBooks Desktop Company file is opened using the Admin credentials, and no Intuit account is associated. QuickBooks users will be prompted to log in or create an Intuit account. Pro and Premier users may choose to delay this action for up to 28 days and QuickBooks Enterprise users up to 42.

For more info, proceed to the Intuit account section of this article: QuickBooks Desktop Intuit account. 

Also, you can always access your QuickBooks Desktop file from the computer it is installed on regardless of internet connection. You'll only need an internet connection for downloading the software if not on disk, activation and registration of your QuickBooks, and updating the product to the latest release. 

Additionally, if your RealmID (company identifier) is not saved in your company file, as a result, QuickBooks will require an Intuit login every time you attempt to open it. To prevent this, please head to Intuit login is required every time the company file is opened  at this link for the detailed steps. 
 

Here's a helpful article that will guide you to manage your data safely and easily: Access and manage your personal data from the One Intuit Account Manager.

Keep in touch with me if you have further concerns about accessing your company file. I'll be around whenever you need further assistance. Take care always.