Hi there, @Chrissy R.
Thanks for posting here in the Community. I can share some insights about how multi-user feature works in QuickBooks Desktop for Mac.
When using the multi-user mode in QuickBooks Desktop, once the administrator turns off the server where the company file is saved, other users won't be able to open the shared file. This is because the database manager is saved to the main server. To better understand how multi-user works, please check out these helpful articles:
However, for the other users to work on the company file, they'll need to save a copy of the original file on their computer. Take note that changes made will not be transferred over to the original file.
Here are some helpful articles that you can check out to about troubleshooting multi-user issues in QuickBooks Desktop.
In case you need additional assistance with this concern, feel free to reach out to our Customer Care Team. To reach them you can follow the steps, provided in this link: Contact the QuickBooks Desktop Customer Support Team.
Be sure to let me know how else I can empower you to make QuickBooks work the way your business needs. Thanks for coming to the Community, wishing you continued success.