Visual studio 2019 unterminating background processes - high cpu use, lag

I have found a half solution to this from msdn. However, its worth noting that the problem has resurfaced in a slightly different form. The below may help some people however.

https://developercommunity.visualstudio.com/content/problem/672009/live-analysis-eats-up-memory-resulting-in-vs-crash.html?childToView=858720#comment-858720

which has the following post:

As a workaround, add a rulset with the following contents:

<?xml version="1.0" encoding="utf-8"?>
<RuleSet Name="MyRules" Description="My Rules" ToolsVersion="16.0">
  <Rules AnalyzerId="Microsoft.CodeAnalysis.Features" RuleNamespace="Microsoft.CodeAnalysis.Features">
    <Rule Id="IDE0067" Action="None" />
    <Rule Id="IDE0068" Action="None" />
    <Rule Id="IDE0069" Action="None" />
  </Rules>
</RuleSet>

You can add the ruleset to your project/solution as follows:

https://docs.microsoft.com/en-us/visualstudio/code-quality/using-rule-sets-to-group-code-analysis-rules?view=vs-2019#specify-a-rule-set-for-a-project

I also had this issue, and was causing my builds to take way longer than it did in previous versions. The tasks seem to just never complete which then led me to believe it was a privilege issue. I suggest finding your devenv.exe

usually located at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE

Right click and open as administrator, then open your solution project.

this actually fixed my issue.