Thanks for working through the suggested solution with us, ainav. Let's troubleshoot your QuickBooks Desktop issue with some straightforward steps. We'll help you resolve the problem quickly so you can switch to single-user mode.

Let's start by downloading and installing QuickBooks Tool Hub. This tool is designed to fix common errors within the application.  For the best experience, we recommend you use Tool Hub on Windows 10, 64-bit.

Follow the steps below on how you can install this tool:

1. Close QuickBooks.
2. Download the most recent version (1.6.0.3) of the QuickBooks Tool Hub. Save the file somewhere you can easily find it.
3. Open the file you downloaded (QuickBooksToolHub.exe).
4. Follow the on-screen steps to install and agree to the terms and conditions.
5. When the installation finishes, double-click the icon on your Windows desktop to open the tool hub.

Once installed, you can utilize the tools available in the QuickBooks Tool Hub. This hub is a launchpad for various tools designed to address specific issues. Each tab contains tools tailored to help you resolve different problems. In your case, you'll need to choose Company File Issues. Then, run the Quick Fix my file or the QuickBooks File Doctor to fix common data issues. If you need more help, select File Dr Help. For your visual reference, check out the attached image below:

Here are some resources to help you learn how to use QuickBooks Desktop on multiple screens with the new Multi-Monitor mode, set up folder permissions, and access folders in multi-user mode:

• Use QuickBooks on multiple screens or in Multi-Monitor mode
• Set up folder sharing
• Set up folder and Windows access permissions to share company files

Let me know if you have more questions about switching modes or managing users. Just drop a comment below, and I'll be here to help you out.