Trouble Starting Quickbooks 2020, Error Code -6210, 0

Thanks for the detailed information, cdhodgdon.

Since you've mentioned that your file is hosted in a network. Let's perform troubleshooting steps to resolve this.

First, you'll need to check if hosting is turned on by pressing F2 and then find Local Server Information. Make sure hosting should be turned off.

Second, you'll need to rename the .ND and .TLG files and run the Database Server Manager from the QuickBooks Tools Hub.

Here's how:

Steps 1: Rename the .ND and .TLG files.

1. Open the folder that contains your company file.
2. Find the files with the same file name as your company files but with extensions .ND and .TLG.
3. Right-click each file, then select rename. Add the word OLD at the end of each file name. Ex: company_file.qbw.nd.OLD

Step 2: Run the QuickBooks Database Server Manager from the QuickBooks Tools Hub.

1. In the tools hub, select Network Issues.
2. Select Quickbase Database Server Manager. You’ll be asked to install QuickBooks on your server if it isn’t already installed.
3. Inside the QuickBooks Database Server Manager, Select Start Scan if you see your company file(s). If you don't, Browse to the location of your company file and then select Start Scan.
4. Open QuickBooks again and try to sign in to your company file. If the same issue occurs, proceed to solution 3.

Solution 3: Open a sample company file locally installed on a workstation

1. In the No Company Open window, select Open a Sample File, then choose from the list of sample company files.
2. If the sample file opens, proceed to solution 4. If the sample file returns the same error message, repair your QuickBooks installation.

Solution 4: Open the company file locally

1. Open the folder that contains your company file.
2. Find the file with the extension of .QBW.
3. Right-click the file, then select Copy.
4. Go to desktop, right-click on the desktop, then select Paste.
5. While holding down the control key, open QuickBooks so you are directed to the No Company Open window.
6. Select Open or restore an existing company. Navigate to the desktop, find the company file you copied and open.
7. If you are still getting the same error, please proceed to solution 5.

Solution 5: Close all QuickBooks processes

1. Log in as the Administrator on the server computer.
2. Press Ctrl+Shift+Esc to bring up the task manager.
3. Show processes for all users by selecting the Users tab.
4. Highlight each QuickBooks process (QBW32.EXE, qbupdate.exe, and QBDBMgr.exe), then select End Task.
5. Open the company file in multi-user mode.

You can also check out this article to learn how to fix common errors in QuickBooks: Fix company file and network issues with QuickBooks File Doctor.

If you have other questions, please feel free to drop a comment and I'll be happy to help you out.

Using QuickBooks pro-2021 and From today's morning, No one user cannot access the company file....I already ran file doctor, but this doesn't work.

Open the sample file.