I do not know how to Fix Error 213 when backing up the company software.

I can assist you in resolving Error 213, @Kbarmt.

This error occurs due to a duplicate entry in QBWin.log. To fix this, you can use the Rebuild and Verify tools in QuickBooks Desktop (QBDT). These tools can fix minor company file data issues automatically. 

Here's how:

1. Go to the File menu in QBDT.
2. Hover over Utilities and select Rebuild Data.
3. Click OK in the QuickBooks Information window and follow the onscreen instructions to save a backup.
4. Wait for the tool to repair your file. This may take some time.
5. When the tool finishes, select OK.
6. Repeat the first step and choose Verify Data this time.
7. Wait for the tool to check your file for data issues.

For more information about the process, visit this article: Fix data damage on your QuickBooks Desktop company file.

If rebuilding won't work, you'll need to manually locate and remove duplicate entries from the list using the QBWin.log file. Refer to this article for detailed steps: QBWin.log: Verify list. Duplicate name encountered.

Please return to this thread if you need additional help fixing the error. It's our pleasure to help you out.