Bug: UE will error when run under a designated worker, if another user (an artist) is using UE in their account

[andymanaws]

Describe the bug

From Unreal Engine 5.4 (?) it looks as though DDC is now provided by a Zen Storage service, regardless if you are using DCC explicitly on your machine image or not.

When UE starts to process a job / startup, it attempts to start the Zen Storage service, but if this has already been started by another user ( e.g. an artist, or a Deadline worker user) then UE throws an error ( attached below) and exits.

I think this is a change in UE 5.4 behaviour but this behaviour prevents a deadline worker running in the background, and will throw a job error, if an artist is using UE on the same machine, in a different account - or vice versa.

Expected Behaviour

Be great if UE could launch specific services/ports for each user ( or share services)

Current Behaviour

2nd Application launch will result in an error./

Reproduction Steps

Launch a simple scene ( e.g. Meerkat) from 2 different accounts - e.g. artist account and deadlineworker account.
You will get an error on the 2nd application launch.

Environment

At minimum:

1. Operating system: Windows Server 2022
2. Version of Unreal Engine:5.4
   3: Version of this package: n/a
3. If this is from a version installed by the Deadline Cloud Submitter installer, then what version of the submitter installer?

Please share other details about your environment that you think might be relevant to reproducing the bug.

[baxeaz]

We're planning on adding some automated testing in the near future which will likely rely on this working, will take a look, thanks!