Question: In the Azure DevOps portal, I select a pipeline, then the [...] menu, then Delete.

I see a message asking:

> 
> Are you sure? This action cannot be undone. This will permanently
>  delete the pipeline 'vt3e (1)'. Deletion includes all builds and
>  associated artifacts.
> 
> 
> 

I type in the pipeline name and click OK but the pipeline does not delete.

I have waited some hours.

**[Update]**

F12 in Chrome shows an error in the console:

> 
> ms.vss-build-web.common-library.\_\_y\_\_CePsj5f5zdcIK.min.js:18 Error:
>  One or more builds associated with the requested pipeline(s) are
>  retained by a release. The pipeline(s) and builds will not be deleted
> 
> 
> 

**[Update]**

I am trying to follow the answer given by David D, but when I go to delete a release I get a message

> 
> VS402946: 'Release-8' cannot be deleted as it is currently deployed on
>  stage(s) Stage 1.
> 
> 
> 

**[update]**

[The issue is logged at Microsoft](https://developercommunity.visualstudio.com/content/problem/324411/deleting-a-build-pipeline-does-not-work.html)

Answer: 
I was having the same problem and tried different browsers, platforms etc. I found that by removing each release manually under the releases tab, going back to build and then trying to delete the pipeline again worked for me.
Go to pipeline runs and click on 3 dots when you hover across each run. You will see an option for view retention leases. Click on that and then click on remove all.
You have to do it for all the runs.
Once deleted then try to delete the build pipeline.