# How the Web Connector opens QuickBooks
Source: https://www.desktopaccountingapi.com/docs/help/guides/no-company-open/

> What happens when the app needs QuickBooks and QuickBooks is closed, open with no company file, open with your company file, or open with a different one, and which to choose.

The app does not need you to keep QuickBooks open. What happens when a request arrives depends on one setting you chose during setup and on what QuickBooks is doing at that moment. This guide explains each case so you can pick the setup that suits your office.

## The setting that lets QuickBooks stay closed

During setup, QuickBooks asked how the app may access the company file. The choice that matters here is **Yes, always allow access; even when my QuickBooks isn't running** (in older releases, **Yes, always; allow access even if QuickBooks is not running**). Intuit calls this unattended mode, or auto login. With it, the Web Connector may start QuickBooks by itself in the background and sign in as the QuickBooks user you picked under **Sign in as**.

You can check it later as **Admin**: **Edit › Preferences › Integrated Applications › Company Preferences**, select the app, click **Properties**, and look for **Allow access for this application even when QuickBooks isn't running** (in older releases, **Allow this application to login automatically**). See [QuickBooks denied access to the app](https://www.desktopaccountingapi.com/docs/help/connection-errors/access-denied/) for the full steps.

Without this setting, QuickBooks must be open with the company file whenever the app needs it.

## What happens in each case

| On the Web Connector computer | What happens when the app sends a request |
| --- | --- |
| QuickBooks is closed | The Web Connector starts QuickBooks in the background, without a window, opens the company file from the location saved during setup, and signs in as the **Sign in as** user. When the update ends, QuickBooks closes again within seconds. The first request after a pause takes longer while QuickBooks loads. |
| QuickBooks is open at the **No Company Open** screen | The Web Connector opens the company file itself for the update, signed in as the **Sign in as** user, and closes it again afterwards. |
| QuickBooks is open with the connected company file | The request runs in the open session, as whoever is signed in. Their QuickBooks permissions apply, not the **Sign in as** user's. |
| QuickBooks is open with a different company file | The request cannot run. QuickBooks lets connected apps use only one company file at a time on a computer, the one that is open. The app reports that a different company file is open. See [A different company file is open](https://www.desktopaccountingapi.com/docs/help/connection-errors/wrong-company-file/). |

In every case the computer has to be on and signed in to Windows, with the Web Connector running. See [Start QuickBooks and the Web Connector at sign-in](https://www.desktopaccountingapi.com/docs/help/guides/start-automatically/).

## Which should you choose?

### Leave QuickBooks closed

Best when nobody works in QuickBooks on the Web Connector computer, such as a server or an office computer that stays on.

- Needs the **always allow access** setting.
- The saved location of the company file must be reachable when nobody is signed in to QuickBooks. On a network, use the server's name rather than a mapped drive letter. See [Open the file by its network path](https://www.desktopaccountingapi.com/docs/help/connection-errors/company-file-not-found/#open-the-file-by-its-network-path-not-a-drive-letter).
- QuickBooks signs in as the **Sign in as** user only while an update runs, so that user takes a license seat only briefly.
- Give the connection its own QuickBooks user, so it never collides with a person who signs in with the same name. See [Create a dedicated QuickBooks user for the connection](https://www.desktopaccountingapi.com/docs/help/guides/dedicated-quickbooks-user/).

### Leave the company file open

Best when someone works in the company file on that computer all day, or when your office shares the file in multi-user mode.

- Requests start faster, because QuickBooks is already loaded.
- The app's changes are made as the signed-in person, and their permissions apply. See [Change the QuickBooks user the connection uses](https://www.desktopaccountingapi.com/docs/help/guides/change-quickbooks-user/#which-user-quickbooks-actually-uses).
- Do not switch to another company file on that computer during working hours. While another file is open, the app's requests wait.
- Close pop-up windows in QuickBooks promptly. An open window blocks every connected app. See [A QuickBooks window is blocking the connection](https://www.desktopaccountingapi.com/docs/help/connection-errors/modal-dialog-open/).

### Leave QuickBooks at No Company Open

This works, and the connection opens the file for each update. It is useful on a computer where people switch between several company files, because nobody has to remember which one to leave open. If you connected several company files on one computer, see [Connect several company files](https://www.desktopaccountingapi.com/docs/help/guides/multiple-company-files/).

## In a multi-user office

When the Web Connector starts QuickBooks by itself, the file may open in single-user mode on that computer for the length of the update. Intuit's SDK guide says that apps that start QuickBooks on a computer that is not hosting multi-user access open the file in single-user mode. While that lasts, other people may be unable to open the company file.

If your office shares the company file, keep it open in multi-user mode on the Web Connector computer during working hours. See [Use the connection in a multi-user office](https://www.desktopaccountingapi.com/docs/help/guides/multi-user-mode/).

## Check that it worked

1. Close QuickBooks completely on the Web Connector computer.
2. Wait a minute, then do something in the app that needs QuickBooks.
3. If it succeeds, the Web Connector can open QuickBooks by itself. If it fails, see [QuickBooks could not be started](https://www.desktopaccountingapi.com/docs/help/connection-errors/cannot-start-quickbooks/).

## When to contact the app's support team

Contact them if requests fail in one of these cases but work in another. Send the time, which case you tested, the exact message the app showed, and a screenshot of the app's row in the Web Connector.

## Related pages

- [QuickBooks says the company file is being used by another application](https://www.desktopaccountingapi.com/docs/help/connection-errors/company-file-in-use/)
- [A different company file is open](https://www.desktopaccountingapi.com/docs/help/connection-errors/wrong-company-file/)
- [Start QuickBooks and the Web Connector at sign-in](https://www.desktopaccountingapi.com/docs/help/guides/start-automatically/)
- [Create a dedicated QuickBooks user for the connection](https://www.desktopaccountingapi.com/docs/help/guides/dedicated-quickbooks-user/)
- [Use the connection in a multi-user office](https://www.desktopaccountingapi.com/docs/help/guides/multi-user-mode/)

## Sources

- Intuit, [QuickBooks SDK Programmer's Guide](https://static.developer.intuit.com/resources/QBSDK_ProGuide.pdf), chapters "Specifying Authorization Preferences" and "Accessing Desktop QuickBooks Editions"
- Intuit, [QuickBooks Web Connector Programmer's Guide](https://static.developer.intuit.com/resources/QBWC_proguide.pdf)
- Intuit, [Fix Web Connector error QBWC1039](https://quickbooks.intuit.com/learn-support/en-us/help-article/multi-user-mode/fix-error-qbwc1039/L2WqXx5LW_US_en_US), on turning on automatic login