How do I set up QuickBooks Desktop for Windows data with multiple users if I've already installed the product?

I can help you set up a multi-user so other workstations can access your company files, Harry. 

To set up a multi-user network in Quickbooks Desktop, it's recommended to keep your company files on your server computer's local hard drive. This simplifies the process of sharing them over your network.

You’ll want to turn on the folder and Windows access permissions to share company files. This makes sure workstations can access and work with your clients. Here’s how:

1. Right-click the folder that carries the company file.
2. Go to Properties, then select Security and Edit.
3. Choose QBDataServiceUserXX and then click Full Control.
4. Press Allow.
5. Click Apply, and then press the OK button.

Once you've done this, follow the instructions below: 
 

1. Press Windows + E keys to open File Explorer.
2. Find and right-click the folder containing your company files.
3. Move to Properties> Sharing> Shared Add.
4. Choose the corresponding QBDataServiceUserXX for your version.
5. Set permission level of both users to Full Control and Share.

You can refer to this guide for complete instructions on  set up and install a multi-user network. This provides you depth information, so everything is properly configured.

I’ve also included this troubleshooting guide in case you’re having issues when you try to switch to multi-user mode. I’m sure this will be helpful.

Don't hesitate to drop a reply below if you have additional multi-user concerns. I'll be around to help in any way I can. 

@Harry D 

Scam again?

@JJ9425 

You can follow the instructions shared by AbegailS_ 

Ignore Harry D