Experiencing QuickBooks Error 6123 when opening or restoring a company file? This common problem often comes from conflicts between QuickBooks and server settings, corrupt company files, or improper backups.
1. Stop all QuickBooks processes.

Use Task Manager to close QBDBMgrN.exe and QuickBooks processes.
2. Run the QuickBooks File Doctor.

Download it from Intuit and let it fix your file automatically.
3. Rename the .ND and .TLG files.

These files manage network data. Open your company file folder, find [companyname].nd and .tlg, and rename them (for example, add “.old”).
4. Restore from backup.

Use a recent backup file (QBB) and make sure it's saved locally, not on a network drive.
5. Configure Folder Permissions.

Right-click the company folder, select Properties, go to the Security tab, and give full control to users and QuickBooks services.
6. Update QuickBooks.

Make sure QuickBooks is updated to the latest maintenance release.
7. Seek advanced help.

If the issue continues, share details: QB version, whether you're on a network or local, a screenshot of the error message, and any recent changes in your system. Forum members and ProAdvisors can provide more insight.
Read More:https://qbookassist.com/quickbooks-error-6123/