# Single-user or multi-user mode conflict
Source: https://www.desktopaccountingapi.com/docs/help/connection-errors/single-user-multi-user/

> Fix errors 0x80040410 and 0x80040422 when the company file is open in a mode that blocks the connection.

QuickBooks has the company file open in a way that does not leave room for the connection. Someone else, or another program, holds the file in a mode that keeps everyone else out.

## What you see

The app shows:

> QuickBooks Desktop is using the company file in a way that blocks the connection. Switch to single-user mode or close other programs using the file, then try again.

The app's support team may see the code `0x80040410` or `0x80040422`. During setup, the title is "The company file is in use".

## Why it happens

A QuickBooks company file is open in one of two modes:

- Single-user mode lets one person, or one program, work in the file and keeps everyone else out.
- Multi-user mode lets several people and programs share it.

This error appears when:

- someone on another computer opened the file in single-user mode, so the connection cannot get in
- another connected program, such as a payroll, shipping or reporting add-on, opened the file in a mode that keeps other programs out
- QuickBooks is doing a task that needs the file to itself, such as a backup, Verify Data, Rebuild Data or a file upgrade

During the first approval of the app, the opposite applies. QuickBooks needs the file in single-user mode, with nobody else signed in.

## How to fix it

### Everyday use

1. Find out who else has the file open. In QuickBooks Enterprise, **Company › Users › View Users** lists who is signed in. In other editions, ask around the office.
2. If someone opened the file in single-user mode for a task, wait for them to finish, or ask them to choose **File › Switch to Multi-user Mode**.
3. If a backup, Verify Data or Rebuild Data is running, let it finish.
4. Close other add-on programs that connect to QuickBooks, then try the app again. If one of them always takes the file to itself, ask its vendor about multi-user support.
5. Try the action in the app again.

### During setup

1. Ask everyone else to close the company file or sign out of QuickBooks.
2. In QuickBooks on the setup computer, choose **File › Switch to Single-user Mode**.
3. Open the connector file again, or click **Check again** on the setup page.
4. When setup is finished, switch back with **File › Switch to Multi-user Mode** if your office shares the file.

## How to check it worked

The app's action goes through, or the setup page passes the check after **Check again**. In the Web Connector, the app's row shows no error in **Last Result** after the next check-in.

## When to contact the app's support

Contact them if nobody else has the file open and the error continues. Send the time, the exact message, whether the file is shared over a network, and a screenshot of the app's row in the Web Connector window.

## Related pages

- [Use the connection in a multi-user office](https://www.desktopaccountingapi.com/docs/help/guides/multi-user-mode/)
- [QBWC1039: Only the Admin can grant first access](https://www.desktopaccountingapi.com/docs/help/connection-errors/admin-required/)
- [A record is open or locked by another user](https://www.desktopaccountingapi.com/docs/help/connection-errors/record-in-use/)

For developers, see [`QBD_FILE_MODE_CONFLICT`](https://www.desktopaccountingapi.com/docs/errors/#qbd_file_mode_conflict).