I've just encountered this issue. We were using Winget to install the Desktop Runtime but now the version is too new and DCU is failing. Really frustrating. Do you know where you found 8.0.17 version?

Actually for anyone reading this you can specify version with winget using --version flag (--version 8.0.17)

Here : https://dotnet.microsoft.com/en-us/download/dotnet/8.0

Open the 8.0.17 paragraph, then on the right.

I've been running in to this for a couple of months now. The runtime installer isn't that large so It would be nice if they could have added it to the command update package. Though I'm starting to wonder if they may be discontinuing it opting for the bloated support assist app. set up 15 latitudes over the past 3 months and the one I received today didn't have the option to even download command update through the devices software and drivers download page. 

This isn't a solution.  We need to keep our PCs updated to comply with Cyber Essentials requirements and older versions have security vulnerabilities. 

Dell should update their applications to use the new versions of .Net 

We had a fleet of machines that were failing DCU 5.6 update.

Awesome this worked for me. Banging my head against the wall forever trying so many different things and installing older version of .net desktop 8.0.17 or lower worked.

Thank you, J

@dfeifer​ Probably this, we switched to Lenovo after having too many issues with Latitudes (5540 and 5550s) and having poor support from them for about a year. These models also had poor mics they refused to acknowledge, despite the testing they recommended showing as much compared to older models. Their sales rep is still reaching out to sell us laptops as if she never read the dozens of support emails she was included on as well as direct emails to her about us ending purchases of Dell laptops if we didn't start getting better support.