QuickBooks Error 6123: Causes, Solutions & Troubleshooting Guide

# QuickBooks Error 6123: Causes, Solutions & Troubleshooting Guide QuickBooks Error 6123 generally appears when you try to open your company file, restore a backup, or access a company file stored over a network. It often halts your operations with an error message like: <blockquote data-start="813" data-end="889"> “Error -6123, 0: Connection to the QuickBooks company file has been lost.” </blockquote> This can be frustrating, especially when working in multi-user mode or while migrating data between systems. Fix QuickBooks Error 6123 with expert-approved solutions, causes, and easy steps. Call +1-866-500-0076 for immediate technical assistance. Read This Blog: <a href="https://www.quickbooksupportnet.com/how-to-resolve-quickbooks-error-6123/">QuickBooks Error 6123</a> <h2 data-start="1006" data-end="1050">What Triggers QuickBooks Error 6123?</h2> Here are some of the most common causes of this issue: 1. Damaged Company File If the company file (.QBW) is corrupted or not stored correctly, QuickBooks won’t be able to access it. 2. Network Configuration Errors Errors in your network setup, especially in a multi-user environment, can disrupt the connection to the company file. 3. Interference by Security Programs Firewall, antivirus, or anti-malware programs might block QuickBooks from accessing necessary files or ports. 4. Damaged .ND and .TLG Files The Network Data (.ND) and Transaction Log (.TLG) files help QuickBooks operate over networks. If either file is damaged, the error can occur. 5. Restoring a Backup Over a Network Trying to restore a backup from an external or network drive without copying it locally first may lead to error 6123. You can also consider visiting this page to learn how <a class="" href="https://www.quickbooksupportnet.com/how-quickbooks-populates-form-941" target="_new" rel="noopener" data-start="1970" data-end="2076">QuickBooks Populates Form 941</a>, which helps ensure payroll tax forms are prepared accurately and may be relevant when troubleshooting related errors. <h2 data-start="2202" data-end="2247">Top Symptoms of QuickBooks Error 6123</h2> Keep an eye out for these early signs: <ul data-start="2289" data-end="2469"> <li data-start="2289" data-end="2331"> Error message “Error -6123, 0” on screen </li> <li data-start="2332" data-end="2373"> QuickBooks crashes while opening a file </li> <li data-start="2374" data-end="2427"> System lags when switching between multi-user modes </li> <li data-start="2428" data-end="2469"> You can’t restore a company file backup </li> </ul> <h3 data-start="2476" data-end="2531">How to Fix QuickBooks Error 6123 – Step-by-Step</h3> Step 1: Rename .ND and .TLG Files These files store network and transaction information and may be corrupted. <ul data-start="2654" data-end="2881"> <li data-start="2654" data-end="2701"> Go to the folder containing your company file </li> <li data-start="2702" data-end="2791"> Find files with the same name as your company file but with extensions <code data-start="2775" data-end="2780">.ND</code> and <code data-start="2785" data-end="2791">.TLG</code> </li> <li data-start="2792" data-end="2881"> Right-click and Rename them (e.g., <code data-start="2833" data-end="2853">companyfile.qbw.nd</code> → <code data-start="2856" data-end="2880">companyfile.qbw.nd.old</code>) </li> </ul> Reopen QuickBooks to recreate these files automatically. Step 2: Move the File to Local Storage If you're trying to restore from a network or external drive: <ul data-start="3058" data-end="3212"> <li data-start="3058" data-end="3096"> Copy the backup file to your desktop </li> <li data-start="3097" data-end="3142"> Restore the backup from this local location </li> <li data-start="3143" data-end="3212"> After successful restoration, move the file to the desired location </li> </ul> Step 3: Use QuickBooks File Doctor Tool This built-in tool can fix company file and network issues. <ul data-start="3330" data-end="3514"> <li data-start="3330" data-end="3376"> Download and install QuickBooks Tool Hub </li> <li data-start="3377" data-end="3426"> Open it and navigate to Company File Issues </li> <li data-start="3427" data-end="3514"> Run QuickBooks File Doctor, select your file, and allow it to scan and fix issues </li> </ul> Step 4: Disable Antivirus and Firewall Temporarily Your security settings may be blocking access. <ul data-start="3630" data-end="3804"> <li data-start="3630" data-end="3679"> Temporarily disable firewall/antivirus software </li> <li data-start="3680" data-end="3738"> Open QuickBooks and try accessing the company file again </li> <li data-start="3739" data-end="3804"> If successful, add QuickBooks as an exception to firewall rules </li> </ul> Step 5: Open the File in Sample Company Mode Testing in sample company mode can help determine if the problem lies in the company file. <ul data-start="3958" data-end="4136"> <li data-start="3958" data-end="4031"> Open QuickBooks without opening a file (press Ctrl while launching) </li> <li data-start="4032" data-end="4063"> Choose Open a Sample File </li> <li data-start="4064" data-end="4136"> If the sample file opens, your original company file is likely damaged </li> </ul> <h3 data-start="4143" data-end="4197">Additional Troubleshooting for Multi-User Mode</h3> If you’re facing this error in a multi-user environment: <ul data-start="4257" data-end="4529"> <li data-start="4257" data-end="4343"> Ensure QuickBooks Database Server Manager is installed and running on the server </li> <li data-start="4344" data-end="4433"> Verify the server is hosting the file (only one computer should have hosting turned ON) </li> <li data-start="4434" data-end="4529"> Use the QuickBooks Database Server Manager to scan the folder that holds the company file </li> </ul> <h3 data-start="4536" data-end="4591">Expert Tips to Prevent Error 6123 in the Future</h3> <ul data-start="4593" data-end="4824"> <li data-start="4593" data-end="4653"> Always copy backup files to a local drive before restoring </li> <li data-start="4654" data-end="4711"> Keep QuickBooks, Windows, and security software updated </li> <li data-start="4712" data-end="4762"> Avoid storing company files on removable devices </li> <li data-start="4763" data-end="4824"> Regularly use QuickBooks File Doctor to monitor file health </li> </ul> Learn More: <a class="" href="https://www.quickbooksupportnet.com/get-a-solution-for-quickbooks-error-3371-status-code-11118" target="_new" rel="noopener" data-start="5265" data-end="5406">QuickBooks Error 3371 Status Code 11118</a> Conclusion QuickBooks Error 6123 can disrupt your accounting tasks, especially when accessing or restoring company files. Fortunately, with the right steps—like renaming support files, using QuickBooks File Doctor, and ensuring network configuration—you can resolve the issue effectively. If manual fixes don’t help, don’t hesitate to contact QuickBooks experts at +1-866-500-0076 for instant resolution.