File or folder permission issues often cause QuickBooks Error 6123. Here's a quick fix for permissions:

1. Run QuickBooks as Admin
Right-click the QB icon and select "Run as Administrator." If this works, it confirms there are permission issues.

2. Enable full control at the folder level
Go to the folder with your .QBW file:
- Right-click, then select Properties, and go to Security.
- Choose your Windows user and “SYSTEM.” Check Full Control and click Apply.

3. Configure sharing permissions
Go to the Sharing tab, then Advanced Sharing. Share the folder and click Permissions.
- Add “Everyone” or a user account. Check “Change” and “Read,” then click Apply.

4. Propagate permissions to subfolders/files
Under the Security tab, go to Advanced. Enable inheritance and apply it to all children.

5. Validate Service Permissions
Open Services.msc, find “QuickBooksDB##” (## = version), right-click, and select Properties, then Log On. Change this to Local System account or a user with full access.

6. Restart QuickBooks services
After you change permissions, restart QuickBooksDBXX and QBCFMonitorService.

7. Test file access
Open QuickBooks normally and try to access your company file. If the error continues, post here with “Access Denied” or details of the error message, along with your version information and OS type. Our users can help identify deeper directory or cloud-sync issues.

Read More:https://qbookassist.com/quickbooks-error-6123/