QuickBooks Error 6129 typically occurs when creating or opening a company file in QuickBooks. It indicates that QuickBooks cannot access the company file due to database connection issues or file corruption. To resolve QuickBooks Error 6129, you can follow these steps:

Update QuickBooks: Ensure that you have the latest updates for QuickBooks installed. Go to the Help menu in QuickBooks and select "Update QuickBooks Desktop." Follow the prompts to download and install any available updates.

Restart your computer and network devices: Sometimes, a simple restart can resolve temporary connection issues. Restart your computer, modem, router, and any other network devices you are using. After restarting, try opening QuickBooks and accessing the company file again.

Rename the .TLG and .ND files: QuickBooks creates transaction log (.TLG) and network data (.ND) files for each company file. Renaming these files can help resolve issues related to file corruption. Go to the folder where the company file is located and find the files with the same name as your company file but with .TLG and .ND extensions. Right-click on each file and select "Rename." Add the word "OLD" to the file name, for example, "company_file.qbw.OLD.TLG" and "company_file.qbw.OLD.ND." This step helps QuickBooks recreate these files when you open the company file.

Use the QuickBooks File Doctor: QuickBooks File Doctor is a diagnostic tool provided by Intuit to troubleshoot company file issues. Download and run the QuickBooks File Doctor tool from the Intuit website. Follow the on-screen instructions to scan and repair any issues with the company file and network connectivity.

Disable antivirus and firewall temporarily: Antivirus or firewall software can sometimes interfere with QuickBooks' access to the company file. Temporarily disable your antivirus and firewall software and check if the error still occurs. If the error is resolved, adjust the settings of your security software to allow QuickBooks access to the company file.

Create a new company file: If the above steps do not resolve the error, you can try creating a new company file and then importing your existing data into it. Open QuickBooks and select "Create a new company" or "Start Setup Interview" to create a new company file. Follow the prompts to set up the new file and then import your data from the old company file.

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Peter