MXD doesn't save SDE data source connections

[AlicePence]

When I add a layer from our SDE it displays fine and I can edit - but when I go to save and close the MXD then reopen it back up the data sources connections are lost (screen shot 1 below) then once I set data source it works (screen shot 2 below). 

To make it more confusing - when I open the MXD and remove the layer then re-add it back in the connection works! 

I have ArcGIS 10.6, SQL Server, and Windows 10

[George_Thompson]

What is the version of SQL Server being used?

Is the SQL Server configured for highly-available?

What if you delete the .sde connection file and recreate it, does the same behavior happen?

I am guessing that you have selected the save connection properties in the connection file.

[AlicePence]

Hi George - we are using SQL Server 2017 and not sure where to find if it's highly available. also when you say 'delete the .sde connection file and recreate it' are you saying delete it from catalog and add it back or create a whole new .sde file?

[George_Thompson]

For the SQL Server side I would ask your DBA.

For the .sde connection, yes. Delete the old connection and rebuild it. I noticed that the "instance" information was different between image1 and image 2. Image1 looks like the old school ArcSDE (dinosaur) information.

[AlicePence]

What is interesting about the SDE connection is that when I open a MXD on my VM (the VM has the SQL server) everything works just fine- where I can save the MXD and the connections are not lost when I open it back up. It's only when I try to save a MXD on my personal machine that this is happening. Not sure why all of a sudden that local machines are reverting back this old 'old school ArcSDE'? 

I tried the rebuild and that still didn't work either, and our SQL Server is highly available.

[AlicePence]

Another test that I just ran too is the MXD Doctor and I can see all the connections and the layers just fine in the viewer - but when I open the MXD the connections are lost. So I'll try to uninstall and reinstall ArcMap and see if that clears it up.

[George_Thompson]

Ok, if you are on the SQL machine and it connects, that would make sense. I think that you have something in the connection file that is not set correctly; Connections to highly available SQL Server databases—Help | ArcGIS Desktop 

Look at that doc if your SQL Server is configured for "HA"

[AlicePence]

Re-installing ArcMap did not help. Also sorry about the confusion, but I just received more information from our team that our SQL server is NOT highly available for both our test and prod environments. Also, I tried saving an ArcScene map (realize that ArcScene does not save as a MXD) but it worked when I saved and reopened again. So not sure why it's only for MXDs that the connections change.

[George_Thompson]

Can you verify the SQL Server native client installed on the DT client: Microsoft SQL Server database requirements for ArcGIS 10.6.x—System Requirements | ArcGIS Desktop 

You should have this one installed:

SQL Server 2017

• Microsoft ODBC Driver 17 for SQL Server

[AlicePence]

I have Microsoft SQL Server 2012 Native Client installed on my machine - it's the same that is on the VM machine that is where the MXD is working