Servers

Are users logging onto the domain?  Is the server R2?  Do you know the functioinality of the forest?

Users are not logging on to the domain, they log on locally.  The server is 2008, not R2.  I do not know the functionality of the forest.  They have had problems with the server, and I have not been involved with that, I believe they had a crash, since then they have been using the router for dns and dhcp, and clients are logging in locally.

are the clients even joined to the domain? If so and they are using domain\username then they are logging in using cached credentials
Fix the existing domain controller or you have to create a new domain and  create the users, shaes, join to the domain. Even if the domain has the same displayed name the new domain will have a different sid.Guessing NO backups right?

Wow, so you can just move the shares over and map them locally.  That would be super easy.  You don't even need to setup a domain on the 2019 server, just shares.

I'd not use Essentials.  You will find much less experience to support you compared to Standard.
I found it to be stranger than strange and never did find out why.
Going to Standard was MUCH easier.

The users are joined to a workgroup, not the domain.  I would like to use the same workgroup name they are using now on the new server.  I am hoping that it will be as easy as copying over files, creating the shares, and connect the users to the new shares.

Sounds to me like you might be better off with some sort of NAS box, not a Windows server.

Netgear, Western Digital and many other venders make cheap NAS boxes that can hold a few SATA drives in a raid array, and support shares that Windows can see natively. Much simpler, cheaper and easier to set up.

I'll second what Mal said. Since this is a business, you want a proper business solution though. I have used Synology for many clients and found it to be very good and easy to manage. Make sure there is also a backup plan as well.

The other option might be some sort of cloud storage.

I've seen installations like this.  Running  Windows Server OS on a machine and not using it for much of anything.  
So, why use a Server OS with no domain?  Perhaps someone else might comment.
Ah!  I see that they have.

I don't like the NAS option, you can't run internal backups and management is too web based.  I agree with Fred, I would get a Windows 10 pro system, you can rdp in so you don't need a monitor, you can setup shares.  Only downside is you can only have 20 users connected.  I think that is the limitation on currently connected users.

I didn't actually say use Windows 10 Pro - although I might have been thinking that.  
And the 20 limit on connections could be an advantage of using Windows Server if there are that many users.

The 20 limitation is on *connections* at any one time.  One User can have multiple connections.  If you have a reasonably active system, you can see the "sessions" in Computer Management / System Tools / Shared Folders / Sessions.
From there you may be able to figure out that there is usually but one "connection" for a Computer.  Occasionally there is more than one showing for a single computer.

If you have concern about the limit of 20 connections, consider that time sharing can be helpful by avoiding permanent connections:

Avoid Mapped Drives
A Mapped Drive setup on a client workstation will create a constant connection on the "server".
So, we avoid Mapping whenever possible (some app's require a drive letter) and use Shortcuts instead.

Avoid Quick Access entries
It appears that adding a "server" workstation folder to a client workstation "Quick Access" also creates a constant connection.
So, don't do it.  Use a shortcut instead.
This one is harder to manage....

With these precautions, I've seen where there are nearly 40 computers / users accessing a single workstation "server" shares.  Time-sharing brings the actual number of connections down to maybe 8 and any one time.  It's hit the 20 limit but rarely and the precautions above have fairly well eliminated those situations.

Fred.

I have been stressing over this project for a while, do not want the stress.
We built the Server for this client, configured it as a domain controller (Server 2008, not R2, and it is 32-Bit.  They had some issues while we were unavailable and changed things.  They, also, had problems with the Internet, and started using DNS and DHCP from their router.  They said they are logging in locally, but I agree with you that they are probably using cache from the DC.  I checked two of their computers, and they are now configured for a workgroup, not a domain.  I had planned to migrate to the new dc, but now I am concerned that there will be problems because of the users.  Do you have ideas that could make my project successful?  I have Windows Server Essentials 2019, and was planning and continuing with the new domain controller, but now it looks like it might be  a nightmare.

Thank you for you help in advance!

Candace

If they hae been out of touch with the DC for that long then the computer accounts have probably tombstoned. Unless the provious DC is still alive that you can connect to it, probably better to start over from scratch with a new DC.

Thank you.  The domain controller is still alive and they are using it.  If I try to replicate the users, will it work even though they are in the workgroup?  Will it cause problems if I start the replication and it does not work?

If I start from scratch, the profiles will have to be re-created on each client computer, is that correct?

I am trying to get this done without too much disruption the network.

Candace:  I'm not the one to best advise on those matters.  I have a lot of experience with peer-to-peer networking and with file sharing in that context.  That's why I responded.

So, I've reviewed the question and am a bit unclear about the objectives.  Here seem some salient facts:
- the Users/Owners had a DC in the past and didn't use it.
- the Users/Owners

Client does not want another domain controller, they want a stand alone server to act as their file server.  The server will be a Windows Server 2019 Essential.

-

I would like to use the same workgroup name they are using now on the new server.

-

I had planned to migrate to the new dc, but now I am concerned that there will be problems because of the users.  

It seems like some things are missing in the big picture:
You don't have a DC unless you have a domain and unless you promote a Server to be a DC.
*Everything* you've said suggests that you want neither of those.  So, just *don't* do that!
You can use either Windows 10 Pro or perhaps you can use Windows Server Essentials.  But the idea is not to create or join a domain.  
A reason then for Windows Server Essentials is that it may get away from the 20-connection limit and maybe help with backup processes.  How many users are there??
I would pay some attention to Dan's comments if I were you.

It *does* appear to me that you can do what you and THEY want.
I might proceed like this:
1) Set up the Windows Essentials Server.  Plan to not join it to a domain.  Plan to not set up a DC.  Plan to have but a workgroup.
2)  Assuming this simple step works:
3) Set up the Server as a File Server.  This shouldn't require a domain to be set up but some "features" won't be available.  The 20 connection limit shouldn't apply.
4) Set up shares within the files to match the organizational needs - workgroup style.  This likely means that client workstations will have credentials OR the Server will have all the user profiles set up.  One way or the other, credentials need to be made available for password protected sharing.
- If you use credentials then they are apparently viewed by Microsoft as in a "cache" and subject to erasure.  So they have to be restored.  Fortunately there is a Save and Restore capability build into Windows Credentials.
The other style is to manually log in each time in reponse to a dialog prompt for logon; but I'm unsure just how robust that approach really is.  Often the dialog doesn't appear and one is just locked out.  
- If you use matching user profiles then they need to be updated with every password update - on TWO computers each time.
With a domain, the user profiles are kept in AD and these pesky little things are no longer needed to be managed.
But, it's certainly doable.
I'd not suggest a "wide open" file sharing system where anyone can see everything without security.

There are plenty of people who will tell you that you *must* have a domain controller if there are more than 5 (to 25) computers.  
I'm not one of those.
I'd not say that it's a bad idea either.
I've been managing 60 computers in a peer-to-peer network (workgroup) with no trouble.  But it does have its security issues that can be questioned if you have auditors.

There is a nice tool from Forensit that will create the new user profiles and join the domain, etc.
How many are there???

There are 10 users

You say there is a domain controller but nobody is logging in to the domain?  That makes me doubt that there's actually a domain controller.  They may call it that .....  I might rather think that it's a box running Windows Server and that's all.  It's important for the terms used to be correct.  How many domain controllers are there?  2 are generally recommended.

Really if all they need is a place to store files and not a "domain", then a NAS such as Synology might be a better choice. It would be easier to manage and probably cheaper, too.