Thanks for checking in with us, Oberon333.

I'm here to help you resolve the multi-user server problem. Let's get this sorted out.

Every version of QuickBooks has a corresponding component that needs to be updated for QuickBooks to function in multi-user. To help diagnose and fix these errors, download and run the QuickBooks File Doctor, which analyzes if your computer is properly set up for multi-user mode or not.

Workstations that have hosting multi-user access enabled can inadvertently go into Alternate Hosting mode and take ownership of a company file. When this happens, other users will not be able to open the file. You may want to verify that permissions are set correctly.

Here's how:

1. Right-click the folder that contains the company file and select Properties.
2. On Security tab, select Advanced.
3. Select QBDataServiceUserXX and select Edit.
4. Make sure that the following settings are set to Allowed.
   • Traverse Folder/Execute File
   • List Folder/Read Data
   • Read Attributes
   • Read Extended Attributes
   • Create Files/Write Data
   • Create Folders/Append Data
   • Write Attributes
   • Write Extended Attributes
   • Read Permissions

If your permissions aren’t set correctly, perform these steps:

1. Right-click the folder that contains the company file and select Properties.
2. Select Security, then Edit.
3. Choose QBDataServiceUserXX and select Full Control, then Allow.
4. Select Apply, then OK.

Verify if QuickBooks Server is running and if the company file is shared.

1. Click Go.
2. Choose Applications.
3. Double-click the QuickBooks 20XX Server.app icon.
4. Share the file if needed:

• If the file is listed under NOT SHARED, select the file, then Start Sharing.
• If the file is not listed, select + to add the file.

You can get more details in this article: Set up folder and Windows access permissions to share company files.

This article is a good reference as well: https://quickbooks.intuit.com/community/Help-Articles/Host-your-company-data-file-in-multi-user-mode....

Should you need more help about multi-user server in QuickBooks Desktop for Mac, don't hesitate to let me know. Have a good one.