“Unable to find manifest signing certificate in the certificate store” - even when add new key

I've finally found the solution and really hope this helps someone else too.

1. Edit the .csproj file for the project in question.

2. Delete the following lines of code:

   <PropertyGroup>
      <ManifestCertificateThumbprint>...........</ManifestCertificateThumbprint>
   </PropertyGroup>
   <PropertyGroup>
      <ManifestKeyFile>xxxxxxxx.pfx</ManifestKeyFile>
   </PropertyGroup>
   <PropertyGroup>
      <GenerateManifests>true</GenerateManifests>
   </PropertyGroup>
   <PropertyGroup>
      <SignManifests>false</SignManifests>
   </PropertyGroup>
   

Go to your project's "Properties" within visual studio. Then go to signing tab.

Then make sure Sign the Click Once manifests is turned off.

---

Updated Instructions:

Within your Solution Explorer:

1. right click on your project
2. click on properties
3. usually on the left-hand side, select the "Signing" tab
4. check off the Sign the ClickOnce manifests
5. Make sure you save!

It's simple!!

I resolved this problem by following this steps:

1. Open project properties
2. Click on Signing Tab
3. And uncheck "Sign the assembly"

That's it!!