Overview

This error message typically displays when you already have a QuickBooks company file with the same name open.

Error: COMException (0x8004040A) A QuickBooks company data file is already open and it is different from the one requested.

Resolving This Error

1. Close QuickBooks.
2. Open Windows Task Manager.
3. Click the Processes tab.
4. Find the QBW32.exe process, select the process, and then click End Process.
5. Restart QuickBooks and open the file.

For help with using the Task Manager, refer to this Microsoft support article.