FWIW: We re-installed the OS and rebuilt the cluster.

Now it works as it should

indeed.

Those settings have been activated.

DTC service has been stopped and started and is on network service

Still Begin distributed transaction fails

Strong suggestion, don't store the images in the database. Can you? Yes. VARBINARY(MAX) would be the way to go. However, it really negatively impacts a whole slew of...

because it has to validate each and every row of the RLS object before it is to be processed by your query

• I avoid images in SQLServer and store their file system path in...

It's called ROW level security for a reason !

So RLS introduces additional processing overhead as the database engine needs to evaluate security predicates for each row.

Of course this...

Pay attention to file / folder security

Start with preparing your new drive ( physical / logical ) by copying the existing folder structures, including their ACL

e.g.

rem especially...

LOL, they don't want their MD to see what illness they have but want to have a treatment for a cure

If you don't trust your DBA, outsource the system and...

• Did you actually configure the instance to work with port 1433 ?
• What happened to your D-drive ?

  It seems the files on D-drive are missing or no longer accessable...

have a look at SQL Server backup to URL"

We all started here as more or less noobs.

Heck, I've also met certified people who had only proven they could learn the content of a book, but weren't able to...

such a shame they wasted all those years of development time SSMS still needed and needs to comply with modern development needs

Can't QueryStore help out ?

We always use an extra sqlagent job step to check it the database is primary.

If not : fail the step and end the job

Else run the next step(s)

how about a NULL set for an answer ?